Piston Slap: From Thriftmaster to a big-cube six shooter?

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Scooter writes:

Is it possible to engine swap a 235 Chevy to a later-model 250 inline-six Chevy in my original factory, frame stock steering box, straight-axle 1957 Chevy pickup truck?

Sajeev answers:

Yes, because anything is possible when it comes to modifying a classic vehicle. It’s even kinda easy when it comes to American vehicles of a certain age, with a strong aftermarket following and plentiful replacement parts. Except that’s probably not the spirit of your intended question.

The 250-cubic-inch six was Chevrolet’s third-generation inline six, and it was significantly different from the second-generation 235.  You can still make the swap, but not without a lot of work that you may not want to tackle, since the engine mounts and bell housing pattern make this a bit more complex. There were numerous other changes with less impact on your swap, but this thread explains the relevant issues in detail.

Odds are you can source the right bell housing and front crossmember to make the swap work, but is that really what you want to do? As much as I love period correct modifications, and while I truly adore upgrades from the same engine family (says the guy who did the 5.0 to 5.0HO swap on his Fox Body Cougar), this one is probably biting off more than one person can chew. Now if you had all the parts to swap over a big boy, tall-deck 292-cu-in engine, that would be the ultimate in period correct stovebolt engine upgrading.

That said, I know our readers have a deeper understanding of these engines than I do. Anyone want to show me otherwise? This is one of those times I’d just love to be wrong!

Have a question you’d like answered on Piston Slap? Send your queries to pistonslap@hagerty.com, give us as much detail as possible so we can help! If you need an expedited resolution, make a post on the Hagerty Community!

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