13 August 2013

Muscle Car Horsepower – How Exaggerated Was It?

Forty years after the end of the “classic” muscle car era, there is still some confusion over horsepower ratings, especially how they relate to today’s cars. Let’s try to clear it up.

Prior to 1972, American carmakers used the SAE (Society of Automotive Engineers) “gross” measurement of horsepower. Gross meant the figure was taken from an engine running on a test stand, with no air cleaner assembly, accessories or exhaust system connected.

By 1971, carmakers began reducing compression in many engines in order to meet upcoming emissions requirements and to use unleaded fuel. General Motors and Chrysler began advertising both gross and SAE net figures in 1971, derived from an engine tested with air cleaner assembly, accessories or exhaust system connected.

The net ratings, which were applied across the board for 1972, must have been a shock to some customers. Suddenly, muscle cars appeared to lose 100 hp or more.

For example, the Corvette’s optional LT-1 350 cu. in. small block V-8 had 370 gross hp in 1970 (with 11:1 compression), then a 330 hp gross rating (with 9:1 compression) for 1971-1972 with a 255 hp net rating. The mighty Chrysler 426 cu. in. Hemi kept its high compression and 425 hp gross rating for 1971 and showed 350 net hp.

Jim Campisano, editorial director of Muscle Mustangs & Fast Fords and Super Chevy magazines, has revisited the classic muscle car horsepower topic numerous times over the years. The magazines have compared old and new muscle cars and have also put classic models on a chassis dynamometer to record rear-wheel horsepower.

“Rear wheel horsepower was at least 30 percent lower than the reported gross figure, in some cases even more,” Campisano said.

Some Super Chevy readers must have been stunned to see that an LS6 Chevelle SS, with 450-hp rating, put down 288 rear wheel hp in the dyno test. That would have put a net hp rating at around 350 hp for that legendary big block.

You don’t need a dynamometer to estimate net horsepower for classic muscle cars, or to check claims of current models. Roger Huntington, the renowned technical writer who penned articles for many car magazines into the 1980s, developed a formula to show the relationship between quarter-mile performance and power output. Others have refined those formulas and developed calculators, in which you can use performance figures and vehicle weight to get estimated hp. (To check hp figures for this article, we used calculators at http://www.stealth316.com/2-calc-hp-et-mph.htm.)

Keep in mind that some muscle cars came specially prepped from press fleets, sometimes with non-factory supertunes. That’s one reason that making comparisons using vintage road tests can be sketchy. Different axle ratios, testing methods, drivers, test conditions and other variables also affect results.

But we can try anyway.

In 1970, Car & Driver tested a Pontiac Firebird Formula 400, which had a 330 gross hp rating and was equipped with a fairly tall 3.07 axle ratio. They recorded a 14.78-second ET at 98.9 mph. A 1970 Trans Am with the same engine, but with a 4-speed and a 3.55 axle ratio, was tested by Muscle Car Review magazine in 1995. That car burned the quarter-mile in 14.68 sec. at 97.17 mph, quite close to the C&D test 25 years before. Pontiac gave that engine a 255 net hp rating for 1971.

Now, let’s add a later model into the mix. When C&D tested a 1979 4-speed Trans Am with the emissions-controlled W72 400 engine, the one with a 220-hp net rating and the “T/A 6.6” decal on the shaker hood scoop, it ran a 15.3 second ET at 96.6 mph. That car had a 3.23 axle ratio. As a drag racer will tell you, the mph figure is the better indicator of horsepower than ET. So, the 35 net hp deficit from the 1971 engine seems accurate, and not nearly as bad as some might have thought three decades ago.

Some myths still persist, though, one being that the 1969-1970 Ford Mustang BOSS 302, which had a 290 hp gross rating, really had “around 400 hp.” Vintage road tests show mid-to-high 14-second ETs at 94-97 mph for a car weighing about 3500 pounds with a driver and test gear. That’s about 100-150 pounds less than the 400-powered Firebirds cited above. Given those figures, the BOSS 302’s 290 gross hp rating seems accurate, pegging net hp closer to 240.

Contrast that with the 2012-2013 Mustang BOSS 302.

Ford rates the modern BOSS with its DOHC 5.0-liter V-8 at 444 hp. Car & Driver, driving one the way most drivers would (not powershifting), recorded a 12.8-sec. ET at 113 mph. Muscle Mustangs & Fast Fords, with hot shoe Evan Smith banging off full-throttle powershifts and the car running on drag radials, scorched the quarter-mile in just 12.07 sec. at 114 mph.

Those similar mph figures easily substantiate the car’s 444 net hp rating and leave no doubt that the 1969-1970 BOSS 302 was at least 200 net hp below that.

To be clear, debunking myths does nothing to tarnish the place that classic muscle cars hold in our hearts and garages.

“We still love the old ones,” said Campisano. “They’re cool looking, fun to drive and fun to look at. It’s just a different performance world today.”

51 Reader Comments

  • 1
    tommy taylor TX August 21, 2013 at 13:06
    By '69 the GM HP number on our Camaro SS was way under the number generated by speed at the end of the 1/4. Lower insurance rate!
  • 2
    Hal Heindel Webster, NY August 21, 2013 at 13:08
    That's about as honest and realistic a comparison of old versus new I've ever come across. Kudos, Jim. I used to own the original factory Dragonsnake CSX2019, which I sold at the Mecum Spring Classic in 2006. Some of the proceeds bought a new 2006 Ford GT and a new 2006 Corvette. Much earlier I had bought the 1970 Boss 302 and 1978 W72 400 Trans Am mentioned in the article. Still own both. "Much earlier" means I bought them new in the wrapper. Back in their day, the Boss and T/A seemed potent enough, but stepping from the modern plain vanilla 400-hp 'Vette into either one of the two is an eye-opener. They're still fun on a Sunday morning, don't get me wrong, but fast? Not any more! Thanks for the reality check. I'm printing copies to shorten future discussions with my die-hard muscle car friends.
  • 3
    Scott Tennessee August 21, 2013 at 13:48
    The older cars gave you that feeling of almost uncontrollable power, because a lot of them were almost uncontrollable. Tires, suspension, brakes, safety equipment, etc... it's all come a LONG way since the late 60's/early 70's. I believe that is the reason that most people feel like the older cars had so much more power... they were harder to control, corner, and stop than modern musclecars, and felt like it. The old cars defintely had personality, though, and also a loyal following. You had to be able to DRIVE to get some of the older cars to perform to their potential.
  • 4
    John Northern Colorado August 21, 2013 at 14:00
    Nice write up. Those of us who grew up living and racing a mile high had to deal with another 20-30% loss due to the thin air. MPH still best indicator of horses. It can't be fudged or corrected, its the same at sea level or 6000'.
  • 5
    Joe Richmond, VA August 21, 2013 at 14:04
    I know that many V6 sedans would hand a classic muscle car its lunch at the strip. Heck, my Mini Cooper S has a working scoop on the hood and runs 0-60 in 6.2 seconds. But classic Detroit muscle captures something no modern ride can: a gone America that was on its way to the Moon with slide rules and Tang. A nation burning rubber as The Yardbirds or Black Sabbath blasted out, innocent of limits, slashed budgets, polluted skies, and practical family matters, like young gods playing with their newfound power. It was just flat-out cool. And finally, doomed. That makes it all the cooler to me and cannot be reduced to numerical comparisons. By the time I got my license in '76, the thunder was rolling off into the distance, then gone.
  • 6
    Jeff So. Cal. August 21, 2013 at 14:50
    That would explain a lot about how my '58 Ford Custom 300, with a balanced/blueprinted 352 C.I, with a 406 solid lifter cam, 10:1 comp. and a toploader 4-spd was kicking butt on both 348 and 409 Chevys, 383 C.I. Mopars, whom I guess now, were lying about H.P.. I had RWHP of 310, pushing my 3800 lb. tank around. So I guess honesty is the best policy.
  • 7
    Kirk Aldrich Genoa,Oh. August 21, 2013 at 14:59
    I had two friends that bought Chevelle's. The 1st.was a 69 396 375 h.p.4 spd.4:10 gear. He added headers,slicks,ran 12.72@ 107 mph. The other was a 70 454,450 h.p auto w/4:10 gear. He added a Eldlebrock hi-rise intake,headers,slicks,4:88 gear and ran 11:88 @ 112 mph. Much better than people give those cars credit for,but still no match for the new technology. I had a 2008 Z06 that ran 11:98 @124 mph.bone stock. I have a friend with a 2006 Z06 w/long tube headers,drag radials,goes 10.98 @ 128 mph. New cars are amazing!!
  • 8
    dan colorado August 21, 2013 at 15:03
    We bought a 2012 Rousch stage3 Mustang last Christmas. I've driven most the supercars over the years and this car does everything alot better. I still have a 64- 440 drag car and a 70 dart. Fun, but no comparison to the new cars
  • 9
    Randolph Jon Geminder Amityville, NY August 21, 2013 at 15:27
    I am the original owner of a '72 Camaro, insured by Hagerty. It was delivered in December of 1971. Those were the days when you ordered YOUR car, with accessories a la carte. I didn't have the money for the SS or the Z28, but I purchased it with the best extras I could, which were: 7" ralley wheels (with white- lettered Tiger Paws at the time), the spoked steering wheel, the four-speed on the floor, and the 350 v-eight. Also (for an additional $100!) the instrument cluster, including all gauges and tachometer. Including taxes, the car cost $3300 - just about one dollar a pound. Though simply called the Sport Coupe, and by no means a "muscle car," it still stands out in a crowd, and runs like a top. Couple that stick with that 350, and by today's standards, it is quite muscular. There are 122,000 original miles on it - onlookers these days inquire as to what kind of car it is, thinking it's some exotic new vehicle!
  • 10
    gary quilliam Freeport, NY August 21, 2013 at 15:44
    I have a '72 340 Duster with a hp rating of 240. As i'm not about to take it to the drag strip, what I'd like to know is if the 72 340 was rated the same way the 71 was rated (at 270 hp) what would the '72 be rated at; apples to apples?
  • 11
    Richard Columbus Ohio August 21, 2013 at 17:28
    I have a 71 Camaro Z/28 350 ci 330 hp , 4sp 410 gear I also have a 2006 Pontiac GTO 364 ci 400 hp 6 sp The Z/28 is real fast but the GTO will fly>>>>>>>technology is amazing>>>>lol
  • 12
    Barry Tiegs Eganville On August 21, 2013 at 17:30
    Well I am a baby boomer and had Chevy SS's ; RoadRunners, Duster 340's and a Camaro in my time plus 2 74 Corvettes- still have one convertible. So I had lots of fun with those vehicles in their time. For their time they were great cars ; especially in a straight line. Of my bunch only the Corvette had better handling and braking for 1974 era. I have driven the new generation Mustangs Camaros and Challengers and am of the opinion that they are much quicker; faster and immensely better handling than the pony cars of my generation; plus the electronics now that in my day was almost non existent. I love the the pony cars of my generation BUT I wouldn't want to be racing for ownerships against the new breed
  • 13
    Andrew Miami, Fl. August 21, 2013 at 17:30
    The old musclecars had a lot of room for improvement internally without ever changing the camshaft. Muscle Car Review once dyed Ram Air III and IV engines. Rated at 366 and 370 hp, they produced 370 and 400 hp respectively with fresh refunds and unported heads. So Pontiacs ratings were honest.
  • 14
    Keith Miller Cypress, TX August 21, 2013 at 17:58
    I am interested in why everyone thinks the muscle cars started in the 1960's when they actually started in the 1950's. Pontiac put some real horse power in their 1957 and 1958 cars. 1958 was golden anniversary for Pontiac and they put a lot into their cars that year. The 370 cu in engine came in 4 different ways from the factory: 2 barrel carb., 4 barrel carb., fuel injection or 3 - 2 barrel carburetors. The car generally came with a 4 speed hydro-matic transmission but could also have a three speed standard transmission. One engine did not make the brochure which showed the maximum horse power at 300 hp. but was a special NASCAR Engine which produced 330 horses and with the 3 - 2 barrel carburetors could make it through the quarter mile in under 13 seconds with a car weighing over 4000 lbs. Something you might want to look into. When did the muscle cars really start appearing?
  • 15
    Brian Pensacola Florida August 21, 2013 at 18:13
    Great article that provides an ability to make an apples to apples comparison. And, as an owner of a 1970 Firebird Formula 400 (335hp, or is that 290?) I'd like to get that 1970 article. Thanks for the good info.
  • 16
    Mr. J home August 21, 2013 at 19:26
    Your numbers sound right to me, especially the Pontiacs. I had a '77 TA 6.6 4 speed 3.23 back in the early 1980s. Though giving up 20 hp to the '79 C&D tested I ran the same mph, 96-97 at 15 flat-14.90s. I did have true duals (no cats) and lighter advance springs in the distributor, pretty much what Pontiac did to get the extra horses IIRC. I then added 1970 RAIII heads and 1.65 rockers, tweaked the secondaries and changed the metering rods, also opened the shaker (for the most part making the engine 1970 specs) now running consistent 13.80s at 100-101 with a 13.78 best. I think the old gross hp figures are useful to show the 'potential' of the engines with some basic mods. Of course we also gave to take into account the well known secret that the manufacturers played games with hp ratings for various reasons.
  • 17
    George Young Loudon, N.H. August 21, 2013 at 20:51
    Hummm, I own a 1969 Boss 302 and have had the horsepower conversation with many people over the years about my car. Your article helps clear up a lot of misunderstanding on my part and any one else who thought the horsepower ratings from that era were under rated. Thanks
  • 18
    Rich C Phoenix, AZ August 21, 2013 at 22:34
    As I've told people over the years, the stories of the 60's & early 70's muscle cars were highly exaggerated and the source or many urban legends. As the article states they were mostly one off, special tuned models for bragging rights and marketing. Today's go fast cars are faster, better handling, stop shorter and don't need the constant 'tuning; the older one's did. I was the one who was doing the 'tuning' on these in the 70's. Carb's, breaker point ignitions I don't miss them.
  • 19
    bob burgett portville ny August 21, 2013 at 10:56
    i own a 70-rs-ss 396 4 speed car and getting ready to restore it. i had a lot of fun with it over the years. last year i bought a 2010 camaro with the 6.2 rated at 426hp, 6 speed. i really love the car and it really runs great. overall i have the best of both worlds, old and new, i love both of them. thanks bob
  • 20
    gerry larrivee erda, utah August 21, 2013 at 23:03
    No mention of the weight : hp ratio?
  • 21
    Don Granger St. Louis August 21, 2013 at 23:30
    I've got a 66 Fairlane GT 4-Speed, 3.25 locker Convertible who's 390 was rated at 335 HP. My daily driver is a 2010 BMW 335 wagon. Both have similar rated HP, and truth be told, the wagon would probably win the drag race between the two and would win a road course race hands down. But... the Fairlane delivers a bigger kick in the pants. There's just something about the old raw delivery of performance that cars of that era had.
  • 22
    Tim Taylor Ogden, UT August 21, 2013 at 11:50
    A related myth is the one that the horsepower rating for the 1969 Shelby GT500 was understated at 335-hp (some say for insurance reasons). It will be interesting to apply this cited formula to calculate horsepower for it. Thanks for the interesting article!
  • 23
    steve the OC August 21, 2013 at 12:02
    The attempts to use modern dynos, old(or cosmetically restored) cars in unknown condition and an absolute lack of tuning really do the old muscle a huge disservice. Hemis, LS6s, Boss 9s,etc still make big power. The claim a properly tuned L88 only makes a few hundred net horsepower is simply ridiculous. In today's age of computer controlled engine management that always keeps the car in perfect tune, its easy to forget that the classic muscle required an enthusiast owner. An hour spent dialing in the old engines could produce big gains-it would still be stock, just set up to run as designed. Another aspect of "the old days" ignored by this test, is that many of the factories that produced the old warriors knew and expected that the stock exhaust, air cleaner, tires,etc would be immediately trashed. Running a COPO 427 Camaro on a dyno with its tiny single exhaust certainly doesn't reveal the true power of the engine. Nor does a Hemi Dart produce any power with an exhaust never intended to be run on the car. When GM tested the ZL1 Corvette way back in 1969, it ran 10s with an open exhaust and sicks and an auto trans. Stock motor-seems like 500+ horsepower to me(yet rated 425). A huge reason for todays great quarter times is fantastic traction management and launch controls. While todays motors undoubtably are better and produce big numbers, trying to claim the legends of old are wheezing relics is nonsense. Let me get a few of the old guard together with a couple super tuned musclecars and we'll show you a true indicator of their power.
  • 24
    Rocco Southampton NY August 21, 2013 at 12:07
    I have a 67 Camaro with a 427 L88 rated at 435hp ,properly tuned has 527 dyno hp ,it run 11.0 in a 1/4 mile all day long
  • 25
    Denny Chicago August 21, 2013 at 12:15
    You missed the BIGEST One the 1967 Corvette 427/435 or L-88 I just bought a GM crate 427 Gen VI and the words they chose was "Conservative" 460hp in the paper work. Enjoy your car! Denny
  • 26
    Suzi Findley Roanoke, VA August 21, 2013 at 12:16
    I own a '70 Chevelle, SS Ragtop with a 396 (402), 4 speed that I recently had bored with more than 375 hp now. Just one question. Why don't you include the '70 Chevelle SS's as muscle cars when they are/were truly some of the top dog muscle cars?... especially if they have the 445 engines in them. Looks to me like some people are Ford biased. Just saying.......
  • 27
    David San Jose, CA August 21, 2013 at 12:18
    I love the classic muscle cars and in fact I have a few in my corral. But there is no disputing the advances in recent years. For example most tests put a 1970 Boss 302 Mustang at 14.8 in the 1/4 mile, at 95mph. Contrast that with a 2013 base V6: 14.0 at 103. Not to mention that the new Mustang will get 30mpg on the highway. That's real progress! (But I will take the '70 Boss 302 over the new one, all day long!)
  • 28
    Bob Magee Butler, NJ August 21, 2013 at 12:22
    When your vehicle is covered by the insurance co. they rate your cost by the horsepower. If it says it's more you pay more. Like motorcycles, some are rated by "CCs" If you have a BSA 650 CC you will pay one rate. If you look the spests up in the factory manual, the actual CC is 648. That s in a lower rate. Always check your factory manuals for the correct HP or CCs.Bob
  • 29
    John Buban Washington State August 21, 2013 at 12:33
    I would think that the true hobbiest of muscle cars would understand the horsepower ratings of muscle cars, and would not be blinded by the change in rating specifications. As an example, Chrysler, for the enthusiast back then, did not give horsepower increases with added performance parts. Chrysler created tables during the 1960's on how to gauge the performance of their cars for the drag strips in changes to both ET and speed. The performance enhancements also included changes in weight as well as suspension changes. A horsepower increase could be ascertained from the increased performance at the drag strip. If you look at the factored horsepower for the various classes of drag racing back then by NHRA, you will see that typically Chryster cars were factored up relative to their claimed horsepower while GM cars were factored down. This was an attempt to level the playing ground. This factoring actually made many B-body cars by Chrysler no longer competitive. So here is another arena where horsepower gets confusing. I personally know that cars are more powerful today than in the Muscle car era. I know they handle better (much of that is due to tire technology). I believe the mistique of the past is a good thing. Finally, I believe the muscle cars of their day out performed everything around them just like performance cars today out perform the grocery getters of today.
  • 30
    Travis Williams San Diego, CA August 21, 2013 at 12:41
    Great article! I own a 1971 Chevelle SS 454 (LS5). Something very interesting to me since I have translated some of these horsepower numbers myself. As mentioned in your article, the change in the way horsepower ratings were measured is a math problem for us that want a real comparison for cars made in 1972 and after. I find it difficult to compare the muscle cars from the 60's and 70's to the modern day muscle cars. Truly "two different worlds!" Regards, Travis
  • 31
    Evan Phebus Scottsdale, AZ August 21, 2013 at 12:50
    Another great article.
  • 32
    Robert Jordan Arlington VA August 21, 2013 at 12:57
    Another point to add in regards to leaded gasoline's used prior to 1971 was the available octanes offered. I can remember 100 Ethel octane was required for all muscle cars of that period. Being that higher octane levels allowed for less advanced timing to burn fully on the power stroke. Once they removed the lead and 100 octane level that's when pre-ignition issues came into play requiring reduced compressions. The other issues showed up 'over time and after many miles' on the eroding of top compression rings and valve guides with the lack of lead causing more blow-by and making less horsepower.
  • 33
    Jimmy Gaines Austin, texas August 21, 2013 at 12:59
    This article is very misleading. At the same time the change from using Gross ratings to Net ratings occurred, Compression ratio was lowered considerably, in some cases cam timing was retarded, more restrictive exhaust was added, cam profiles were changed, all resulting in the engine itself absolutely making much less horsepower. And as far as the Boss 302 engine goes, the only stock quarter mile times done in magazines used very stock cars with high axle ratio and street tires. It is simply impossible for this motor not to have been well over 300 horsepower ( this engine used 351 cleveland heads , which are some of the best flowing factory heads ever made.
  • 34
    Ian @ Jewel or Jalopy Portland, ORE August 22, 2013 at 01:52
    It's also not just about the peak number, it's about how much power you have throughout the usable RPM range. You don't drive a car at one engine speed.
  • 35
    Vern Virginia August 22, 2013 at 19:55
    My '03 Mustang Cobra just dynoed 468 HP at the wheels. with bolt on mods and a tune. My '74 vet L 48 is a rated at ,I think,, 195 HP net. Both are fun cars but from a different time.
  • 36
    Harvey Mushman South August 22, 2013 at 08:51
    Myths indeed. Not hardly. I was there!
  • 37
    T. Saxe Grand Rapids August 22, 2013 at 09:37
    I have had a few muscle cars (insured by Haggerty, too) and never restored them to the low HP factory specs. They looked factory, but with my 1968 KR Shelby Mustang, I left off the snorkle and smog equipment. With my Buick GS 455, I had the engine built to Stage 1 specs with modern pistons, cam, valves and so forth. Vintage muscle cars are indeed all fast and fun, but I sincerely believe that we are presently in the golden age of horsepower.
  • 38
    rex morley Rose Hill, Ks. August 22, 2013 at 12:33
    In 1989, we took our 70 LS6 Chevelle (about 18,000 miles on the clock then) to the local strip (WIR), to see what it could do, validate it's ability, and with heat wrapped 2 & 1/8" hooker headers (closed), with full 2 & 1/2 half standard bent bent exhaust piping in stock configuration, with so called "Turbo" mufflers, a carb base heat shield (homemade and polished aluminum 2024 - T3 .040 plate), along with L-70 x 15 (on mags, stock was 14" rims), Goodyear tires turning the 12 bolt 3.73 posi gears, 4 spd M22, and ran a best of 13.23 @ 113.xx mph in the quarter. I don't recall the 60 foot figures, but at the time, we saw that the 60 foot times sucked for the outcome from lack of any decent traction for at least 120 +/- feet. Except for the above mentioned mods, the rest of the vehicle was stock, as it is today, and still powerful feeling at 44,xxx miles and while we have a couple of more modern performance cars that I'm sure would best this beast on any surface, that feeling from the old LS6 under WOT is still hard to beat.
  • 39
    Ron Wahl Michigan August 22, 2013 at 12:39
    We owned a 1970 BOSS 302 and loved the look, but not the lack of torque down low, especially with a 3.50 gear! The new '13 BOSS literally blows the original away, performance wise, with a similar look! Way to go FORD!
  • 40
    Hal Thayer Santa Rosa Calif August 23, 2013 at 13:22
    I have a 1967 Camaro RS , I don't have a clue what the Gross/Net HP is ,the gear ratio or original specs were....don't care !! At the time it had only the 210 HP , 2 barrel carb 327 motor and it still had plenty of "Power" ...I know because I used to drive it to High School...yeah ,there were a couple Mopar and Big Fords around at the time but the the RS jerked my Head and put a smile on my face. Luck would have it my Mother was the original owner and " Repossessed" it from me ! Now , 46 years later , it still has the stock block , but I put a 4 barrel with an Eddelbrock manifold , Headers and Flowmaster Exhaust...it still jerks my Head and puts a smile on my Face !! As far as the New Camaro , I don't even like them...feel like I am cooped up in a tiny Box,can't even enjoy the better Technology and specs...and though the Style is Retro Cool, it still ain't "as" Cool !! Wouldn't trade my car for 2 new ones...OK maybe 3 or 4 of em ! My Mucles aren't what they were at the time but the Cars are.Muscle Cars of that time were, are, and always will be "The Best" . O to 60...who cares, its all good ! Know Mom would still be proud of her Baby , ( got her name on the Plate) and proud of me for not letting her "Get Away"
  • 41
    Norm Kentucky August 23, 2013 at 06:03
    Were the test on the original Boss 302's done WITH the factory rev-limiter still connected? Makes a difference!
  • 42
    billcamino San Diego August 23, 2013 at 10:29
    1970 Trans Am had a 455.. not the same 400 as the Formula..
  • 43
    Chuck Klim Newton,New jersey August 23, 2013 at 22:34
    Great article, I had one of the most under rated muscle cars, a 71 Boss 351 that I bought new. This car ran 13.4 @ 106 mph and was bone stock except the rev. limiter was disconnected. It was rated at 330 hp at the time. Today I have a 2003 Mustang Cobra That runs 11.61 @ 121 mph and can get 25mpg, just love the modern tech. I have this car and 2 old tractors insured by Hagerty.
  • 44
    Harold Johnson San Francisco bay area calif August 25, 2013 at 03:55
    Unequal comparisons ! Old school got it done with; heavier cars that had a REAL rear seat and trunk, way fewer gears ( 3 or 4 ) vs 5 or 6 speeds today ! Tires were not as preformance constructed. etc etc. My 1974 z28 4 speed has surprised me AND many modern "computerized" vehicle owners during a throw down on the freeway from 50 mph to as far as we dare take it---even though I changed the 3.70 rear gears to 3.08 for better fuel economy !! I know for a fact that it's not just hp to weight ratio, BUT if my 74 camaro had a 6 speed manual with overdrive, both off the line and mpg numbers would be awesome !!! Anyone with an overdrive tranny would get lousy gas mileage if they drove at 65 mph in 1 to 1 tranny drive instead of 1200 rpm 6 th gear !! I still toy with the idea of putting my spare 496 cu in square port bb chevy in my z28 -- can't decide between a road race 5 speed or 6 speed tremic with those super low 1 st gears --- can you see a dodge viper owner thinking twice ??
  • 45
    Jack United States August 26, 2013 at 22:32
    I am a former Chrysler power train engineer. The 426 Hemi ran between 485 and 510hp on the dyno with air restriction (dyno inlet and filter), water pump, alternator without load, and cast iron headers. Tuning and and prep had Jerry Stahl's '66 B body running low 10s in factory stock. Every once in a while, one of these engines would come from the factory close to blueprint specs, and some lucky person had a nice ride. By the way, I own a 4spd '68 Hemi Charger R/T with 13k miles. Eat your hearts out!
  • 46
    John Kranig canton michigan August 27, 2013 at 18:02
    In comparing acceleration performance of today's cars with ones of 40 plus years ago it must be remembered that the tire technology has had a major impact on vehicle performance as well. For instance a 1970 Boss 302 with modern tires would have much better acceleration numbers. I know that basically stock 1970 Boss 302's with slicks would run in the mid 13 sec. quarter mile times just due to the ability to transfer the power to the road surface. I have talked with one of the Ford Boss 302 engine development engineers from the 1969-70 years and he quoted the gross dyno hp as being in the 370 hp range with the Ford "B" curve hp in the 315-325 range which is nearly net except for exhaust system power losses which were not to much on the Boss 302 exhaust system. So the 290 hp advertised maximum wasn't far from the true net value I believe.
  • 47
    Peter Clark Newmarket Ontario, Canada August 29, 2013 at 12:29
    Power?? to scare your pants off and make your knees turn to jelly? That was my 69 Dodge Coronet RT with its 426 HEMI & Isky 550" Solid cam & MT Headers & DANA 60 456 Gears on only 15" Cragar SS wheels and bias ply tires, it ran 11.6 in the 1/4 mile at 125MPH and 180 MPH on the stock 3:23 gears when I changed the neck-breaker gears. Today my new '13 Challenger SRT-8 392 (6.4L) HEMI has 492 HP with all the gizmo's I would liked to have had back then and it winds up real fast and I suspect not much will beat it! But give me back my ''68 Hemi and I'll give her a hug like I did back in the day Maybe it's the tires & hyd suspension and steering that seems to calm the performance today but even though I love the new MOPAR, not until Chrysler stuffs a modern 426 HEMI with that secret dual overhead cam will the performance world see the most blazing engine that wass ever built!! Yeah, I' still living in the past because we were the pioneers of street & strip racing and because we were the first, it seems nothing else can ever come second. MOPAR or no car!! FORD (Fix or Repair Daily) and GM's I'm just sick and tired of everybody bragging about their small block Chevy 350's, there are too many of them, I was never beaten by any of the competition, quite honestly and yeah I had a few of them too.
  • 48
    Garrett Pierce Michigan August 30, 2013 at 22:06
    One thing you neglected to mention here is the quality of gasolines available for modern engines today vs. those required for the musclecars of yore. Different world indeed, since many of the strongest musclecar engines from 40-45 years ago would struggle to run on the modern "junk" gas available today. Sure you can do things to compensate, but it's still not the same as what was available back in the heyday of those old cars. Horsepower ratings have always been a huge debate among those who believe their car to be better or more powerful than others, but the speed calculator never lies. It is what it is. I do find it very interesting that when i go watch "Pure stock" musclecar drags, the times being recorded by many of these original old cars is still substancially quicker than what was ever recorded back in the old days, which is saying something since many of these supercars are running on original type rubber(Firestone wide-ovals/goodyear polyglass GTs) since the group here in Michigan doesn't allow running slicks. Although most of the quick cars are dyno tuned, you can't argue with 11.0s and around 120mph from L-88 Corvettes, high 11s from L-78 Novas and Camaros, plus lots of GTOs and other cars running in the mid to high 12s all on original rubber from 45 year old engine designs. Today's cars are nice, but the expense of them sure makes them just as prohibitive to younger car buffs as those old ones did. That much will likely never change.
  • 49
    Don Misler East coast August 31, 2013 at 07:06
    It's personally what the individual wants, like a lot of us that for any reason, couldn't afford or didn't buy the "original" then, but enjoys it now! For me my "72" stingray (year I graduated) takes me from (almost) 60 to 18 in about the time it takes you to smile. Enjoy what you own! Own what you enjoy!!
  • 50
    Tominator Cahokia August 31, 2013 at 22:47
    I lived through the days of SAE v. NET Hp ratings....made a good read but as some alluded to it was the reduced compression that stopped the HP wars...I lust after my Olds Starfire BTW...10.25 ratio proudly displayed on the air cleaner.Those old cars were slow regardless of HP rating compared to the CID of today. I've had over 75 cars trucks and motorcycles and dragged raced many of them and even set some track records. I miss them but also embrace the technology that makes those old Muscle Cars relics! Enjoy them and restore them but accept the fact that old is slow........Damn! I want my 428 Cougar back.....but my HHR SS does EVERYTHING better......including the 1/4! Oh, that's my DD.....My Ranger does 12.5s in the quarter and still retains every amenity know to man......brag all you want...today is much better...now where's my HEMI cup holder?
  • 51
    Anthony Brooklyn January 4, 2014 at 11:43
    So basically what you're saying is 70% of people are lying about what their cars did back then? Only one way to prove it. Bring the cars to the track with a good set of tires and high octane gas. Slowly detune or tune from there depending on results. The end. I like both old and new muscle cars but this debate is getting dull after all these years.

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