Wanted: 261 Chevrolet engine

[Phil Waterman]

Hi All

If you find a good running 235 or 261 that leaks oil at the crank seals, do not despair or assume that rebuild is only fix. I have had good luck with speedi-sleeves at both ends that and new seals will help a lot. The other thing to watch concerning the general health of these engines as to is a rebuild needed, oil pressure 20PSI at 2000RPM. Both of my 235 & 261 are running well above 35 PSI.

Keep up the search they are good engines.

Chris if it is not going in a Pat 11 or 12 it should be an easy fit. One question right or left side clutch?

Cheers Phil

[Hanno Spoelstra]

Interesting topic. With the relative abundance of GMC 270 cid engines compared to the Chevrolet 216 / 235 / 261, that is the engine of choice here for conversions. I know of one HUP and one C60S here in Holland with GMC 270 engine swaps. Another C60L I know is fitted with what could be a 235, I will check.

How does the GMC 270 compare to the Chevrolet 235 / 261, both in performance as well as modifications needed to make it fit in a CMP?

H.

[chris vickery]

Not too sure how they compare but the main difference is the block.
The 216/235/261 all share the same block, so mounting and fitting motor mounts, transmissions etc is interhangeable.
The 270 is a whole different animal.

[Bob Carriere]

...only by a few inches but significant enough to have the nose section of a C60X with the 270 sligthly modified for the extra lenght..... bell housing attachements are also different and requires two smaller brackets instead of the usual CMP one piece.

The Caldwells had a HUP with a GMC engine and the engine cover would not fit due to lenght.

Cheers

[motto]

My perception of these two engines is that the 270 is more likened to a Clydesdale with a goodly amount of grunt but no sparkle. The 261 comes out of the stall eager and impatient to get going with instant response. It brings the truck alive. (G506. Originally these trucks had a 235 splash feed) I put 9.00-20 tyres on in place of the 7.50-20s for a recent 200+mile round trip and the 261 handled them with ease. Definitely a better proposition than the 270 if you want to up engine. The block length alone makes a good argument for that.

David

[cletrac (RIP)]

If you're looking for power go with the 270s big brother 302. It was a good truck engine.
The 261 is a higher rpm engine than all the others and hence has more zip. A good 261 could handle a 283 V8 in a similar sized vehicle. I have 3 or 4 261s that need overhauling. They're a direct replacement for a 235.

[chris vickery]

Now that we are straying off target here, the intention was a direct replacement for a stock 235cid. No modifications, no hotrodding etc. Respectfully, 270's, 302s etc have their place and for this discussion this is not it.
While I am a purist at heart, I am also a realist. Physically, the average Joe cannot even tell the subtle differences between a 216/235/261 block. It is the small details that make it so. Internally it is a whole different story.
Back in the day, the term "sleeper" was used to convey a vehicle that from it's outward appearance was a normal, stock built car. What was under the hood was something again. In the case of HMVs, the inferior 216 has and is often replaced with the better built 235 for the interest of reliability and durability. The engineers at Chevrolet figured out how to make a 216 better.
If a fellow can essentially put a better engine with more horsepower and torque under the hood without sacrificing originality, why not?
If you had a choice of more bang for the buck and have to rebuild your old 216 or 235 why not go for bigger and badder?
BTW, a stock 216 is approx 80hp I believe and a stock 261 is 148hp.