The Stovebolt Site Forums The Shop Area Engine Shop Is a 261 worth the trouble?

I have a line on a 261 core that I can probably get for very little money. Of course, rebuilding an engine....be it a 235 or a 261....will cost several dollars.

Wondering if those who have run both the 235 and 261 could weigh in with an opinion. From a “seat of the pants” perspective....is the extra displacement of the 261 noticeable on the road? I’m talking about mixed town and highway driving of a 1/2 or 3/4 ton pickup. Not hauling a load of grain to the elevator in your 2 ton.

Here’s my working hypothesis: The road-drivability difference of 235/261 is negligible, perhaps limited by the antiquated transmissions and high numerical rear ends. If a guy wants to rebuild a stovebolt, the extra headache/cost of sourcing some of the 261 specific parts isn’t worth it.

I have little to back that up. Just hunches. Happy to be proven wrong by someone with real-world experience.

I think the answer will lie in what you put behind the 235 (or 261). If you have a stock transmission and rear end, the 261 will give you more torque but for mixed town and highway driving I'm not sure the difference will be that great. Costly, yes. More noticeable the more weight you're dealing with I'd say. If you have a rear end with a ratio like 3.08, then yes...any extra bit of torque will be your buddy.

But you know in 1959 Chevrolet changed the cam in the 235 to improve torque output at lower rpm, yes? 217 at 2000 rpm as I recall. 261 of same date would have produced 235 at 2000 as I recall, so sort of pricey for the bit extra after the cost of rebuild.

The only real difference in a 235 and a 261 is the bore size. All the other 235 parts will fit- - - -crankshaft, rod and main bearings, cylinder head, etc. are the same as a 235. Pistons and connecting rods are different, but the rods can be reconditioned and reused. Getting 30 cubic inches more in a drop-in fit package is always a good thing, just from a torque standpoint. That was the reason the engine was designed for medium duty and big trucks, and there will be an even more noticeable difference when that engine goes into a pickup.

If you decide not to pull the trigger on it, I'm interested- - - -I've only got three of them stockpiled so far!
Jerry

This one is rough. One cylinder took on water. Looks to me like a significant overbore, perhaps even a sleeve.

Sleeves are no big deal when one has a boring bar stashed away. Do you have an idea of the current bore- - - -standard or oversize?
Jerry

I went from a 216/3-speed to a 261/4-speed in my 1953 3100, with big thanks to Hotrod Lincoln!

Bottom line: It's still an old truck constrained by a 4:11 rear and stock suspension and drives largely the same.

Going from 92 hp to 140 hp, yes you definitely notice a difference throughout the RPM band, however it's not an incredible difference. It pulls harder at wide open throttle in all gears, and can easily pull a hill at 20mph in 4th gear given the extra torque.

I'm certainly no expert, but I have driven a few of these trucks in stock configuration, 1/2 tons and 3/4 tons. From a driving standpoint, I just didn't see a huge difference between a 235 and a 261.

If you're in Kansas City any time, hit me up and come drive mine.

I would sooner go with a good condition 216 with a T5 transmission and a more modern axle than to swap a 261 in place of a 235 with the original transmission and torque tube.
Why?
Because even with the 261, it will be screaming in third gear at 55 MPH.
There is so much more to gain in regards to performance with a T5 swap than from selecting a different Stovebolt engine.
Every time you shift gears, you find yourself in the optimal power range of whatever Stovebolt engine which you have. No more lugging along until it screams, then shift, then lug, wash, repeat.

With a fair amount of tinkering, a 261 can become a 290-something cubic inch engine. That's somewhat better than a 258 CID "216" or a 270 CID "235" if you believe in the old adage "There's no substitute for cubic inches!"
Jerry

I have run them both. The 261 is worth the trouble. More torque, more power. Better drivability getting around town, on a highway. The extra 30 cubes makes a difference.

Haven’t seen it in person. Only pictures. Buddy of mine has it.

One sleeve costs a lot less than a whole set of oversize pistons. If you decide you want it, my boring equipment loves to travel!
Jerry

I am no expert on these, but was under the impression that the 235 was a splash oil system, and the 261 actually had a circulating oil system. So, my ASSumption has been that the 261 would last longer. Please correct me if I am wrong.

The 235, if my memory is correct, was pressure oil in powerglide 53 chevy cars for sure.

The 261, if my memory is correct, came out in only the two ton trucks utilizing the cam shaft from the early corvette to help with torque in the trucks..... I think.
I have a 261 i built in my 50 chevy coupe and while it is not on the road yet the engine sure runs sweet up and down my street and I've had the 216's/235's ect.

235 was a splash oil system, and the 261 actually had a circulating oil system
All 216 and earliest 235 have splash to the rod bearings. Later 235 and all 261 have pressure to the rods.
All have pressure to the main bearings and oil recirculation.

a 261 increases displacement by almost 11% over a 235, no other single change you can make will do that.

The 216 and early 235 engines were directed spray lubrication (and dippers) that fed oil to the rods.

Later 235s and all 261 had fully closed engine lubrication systems.

Earlier engines were true splash oil systems.

here is a little documentation of stovebolt engine lubrication from 1948-1953

here is a description of a full dipper lubrication of rod bearings (directed open-flow of oil at higher RPMs)

here is a "splash oil" system - it has dippers but no directed spray

im new so ill just say my 235 with 848 head and 261 cam has plenty of power with 4.11s . im not sure if it will pull the 3.08s im planning on but id luv to here how it has worked for others !?