The Stovebolt Site Forums The Parking Lot Big Bolts Engine/tranny options for a 42

So my 42 1.5 ton runs, but it's not fun to drive. The engine (235) was replaced in about '55 and then re-built in about '63. That's where the trouble started. The head was ground at all the wrong angles and it can't be machined back to spec. I had the engine re-built in '09 during the restoration and about all we could say was "it runs". And a non snychromesh trans is not great for parades. What engine and trans combinations could i replace with. what would fit? I'm all over the the wood box on this truck but engines aren't my thing - yet! thanks

Some put in T-5 trans. Those trans were used in Chevy S-10's, Camaro's and many more...they mount right up to many of the inline 6's fairly easily from what I hear...This might be an easiest way to go.

If I were to rebuilt another truck I would put a 261 and a t-5 since those just bolt in and look close to original to the untrained eye it wouldn't compromise the original style...or you can always get a 350 sbc.

It all depends, what kind of upgrade your looking for?

Or you can just put in a newer 235 (insert motor) with more power and keep the truck pretty much original. It will bolt in.

Find a SM420 and swap it in, they are made for the big trucks and are almost bullet proof, the T-5 is for the little trucks and cars.

Mike B

Great idea, I didn't even think about that. Isn't the SM420 basically the same trans but it all synchoed except 1st gear?

Yes, it's the granny gear 4-speed that Chevrolet used for years and years (early 50's into the 60's).

Mike B

Not sure the sm420 will bolt up. The bell housing bolts are a different spacing. If you change bell housing you will loose the pivot for the brake and clutch!

Not much for trans options without major fab work.

I'm going through this on my 4bt swap on a 44 1.5t. The engine needed a newer bell housing(from a sm420 trans) the bolt holes didn't line up with original trans. Then I noticed the clutch and brake pivot didn't have a spot to bolt up to. Now my current plan is a 4l60e from 01 blazer and stand alone controller with brake pivot from 49 1.5t frame. Not sure how that is going to fit yet!

Rh

Jim Carter sells a modified bell housing that has the brake/clutch attachment for the Deco model and works with a SM420.

Another vote here for the 261 cu. in. stovebolt six. Chevrolet built these motors specifically for large truck use and the torque characteristics would suit your one and a half ton well. Use the Carter bellhousing that Paul mentioned and the SM420 is a bolt in proposition.

I still have the crash box behind my 261 and you'd be amazed at how smooth they can shift once you get the hang of rpm matching and double clutching, granted not for everyone but a lot off fun once they're mastered!

-Mike-

Thanks for all the input. A 261 sounds like a good option. Is there a particular version/year/casting to search for? Any reputable sources for engine and/or the sm420? Midwest would be preferred but retirement allows for "have engine,will travel".