The Stovebolt Site Forums The Shop Area Engine Shop 235ology 101

I hate to keep launching this thread but I am anxious to understand the engine question in my new 52 panel half ton as the motor represents the most costly and critical decision in the redo. I've decided to restore the truck this winter into a daily driver.

I can get my hands on a Mercruiser 454 Mag or 500 EFI used for cheap with my contacts here. Fuel injected, loads of power, no smog. But then the car becomes somewhat of a hot rod. And the steering column has to be redone, etc. I kind of like the idea of having modest but adequate power. I don't know much about the 235. But I hear you guys talking about upping the ante to the 261 for various reasons. There I go changine engines, though. The original "updated" or a big block sound better for some reason than a bigger, better six.

For a few thousand dollars can the 235 be full flowed, bored, (maybe stroked), moderate cam, bigger valves, ported, etc, and result in a, say, 150hp motor that is tame and easy to daily drive?

I do know that a stock 327 or 350 will provide all the power that I'm looking for and then some. So what to do here. Help. I want to start this process but don't know enough yet. Thanks. Richard Myers....north of Dallas TX

The easiest way to upgrade your existing motor would be to use a '54 235 which has full pressure oil but is still the right length.

You aren't going to make the improvements you want without taking the motor out, so changing to another one, like the 261 or a 270 or 302 GMC seem to me a good approach if you want to look original.

But then I tossed the 235 from my '54 and am in the process of updating suspension and installing a small block in it.

I have a GMC 270 in my 55 1st series, but have a 454 waiting on an engine stand for it, so my judgement might not be what you're looking for...

For what it's worth I just sold off one of my '54 half tons which had the 54 261 with Corvette cam and dual exhaust. I was impressed with the pull on the freeway when some onramp jerk would try to merge into my fender; I could pass with ease. Only problem was the rear end gears kept me limited. The slow lane is where jerks often can be found merging!. The engine looked very original and had lots of torque. I did not do the swap but acquired it that way. I am swapping a 235 into my other one now and it seems fairly easy, as long as you've got the correct parts!

paddywagon,

It sounds like you have a Chevrolet Panel Truck. What year?

"For a few thousand dollars can the 235 be full flowed, bored, (maybe stroked), moderate cam, bigger valves, ported, etc, and result in a, say, 150hp motor that is tame and easy to daily drive?"

If you want to maximize your power improvement and minimize the modifications that you would need to do, the 1954-1962 261 truck engine is a good choice (around 125-135hp, stock). The 270 and 302 GMC engines are longer and would require modifications: http://www.stovebolt.com/techtips/engine_swap2_302.htm

Compared to a 235, the 261 has a "moderate" cam (the same as used in early Corvettes), better valves (not sure if they are bigger), bigger bore cylinders (same stroke), and slightly bigger jets in the carburetor.

All 261 are high-pressure oil systems and the 1958-1962 261s have full-flow oil filtration systems.

The best power improvements to a 261 are obtained by changing the carburetor/intake-manifold (to dual carbs or to a 4-barrel) and changing to a dual exhaust manifold. Neither of these changes require signficant mechanical modifications.

These modifications are simple compared to swapping out for a 327/350; however, the power improvement with a 261 won't come near what you will get with a 327/350.

You will need to decide upon how much power you need/want, how much modification you are willing to do (or are willing to look at), and how much you want to spend.

Tim