My 59 El Camino 235 has a bad motor and I found a running 261 engine from 62, Are these 2 engines the same length? Would this be a bolt in for my 59 EL?
62 what? They came in larger trucks, not in cars. Just make sure to verify it's really a 261 if you're paying extra for it being one. The 261 has a full flow oil filter, the oil lines to it are much larger than the tiny line to the byp*** filter on a 235. Also there might be "captain's bars" on the p*** side of the engine near the starter, check the casting number there, etc. Could be you lucked out. could be someone is selling you a con.
yup it is a 261 the casting number is 3759365. I told him to start this thread to find out if it is a direct bolt in swap
Water pump position is different - depending on your application you may need a short shaft water pump. Here is some interesting read for you: https://www.stovebolt.com/techtips/engines/261 rebuild/index.html
The water pump is the same from 55-62 on both engines, isn't it? If he were installing it in a pre-55 car or truck that would be a concern?
yeah, this is going in a 59 el camino that was born with a 235, you are saying the place that the pump bolts to is in a different spot than a 235??
Should be a straightforward swap I’ve got one the previous owner swapped from a full pressure set up to the earlier set up. Used the earlier oil filter with the smaller fittings. Didn’t help it any.
I've read that some Canadian Pontiacs came with 261s. I have encountered some really early 261s that had the full flow ports plugged and set up for byp*** filters. I have no idea why one would do that, but the 'feature' enabling it is there. I've also purchased a couple of brand new short blocks with bad cranks and bearings that had had that done incorrectly. Chevy dealer too, way back in the 60s. Repaired both and sold them to replace 235s. Bolt in.
The 261 was the base model engine in Canadian Pontiacs from '55-62 I believe. The Canadian version had hydraulic lifters, fiber camshaft gear and were not full flow oil. I seem to remember reading somewhere that there was a GM issued fleet warning about the oil lines developing pinhole leaks and causing under hood fires so presumably some fleets removed them.
The 261 should be a direct bolt in in the 59, I had a 59 Elkie with a 235 for a few years. According to The Filling Station 235 and 261 used the same water pump from 55 to 62 be it car or truck. on most applications. It is the early 216/235 that you have pump issues and pump location issues. One issue with swapping pre1963 Chevy straight six engines around can be throttle likage. The only real difference between the two is the bore, 235 is 3-9/16 an 261 is 3-3/4. Scroll down this PFD on 62 trucks for comparisons on the two. Have fun, Remember that if it is a stick you have to pull the trans, pull the clutch, VERY CAREFULLY remove the flywheel, then reach up and in and unbolt the engine from the bellhousing before you can remove the engine. I usually stick an old input shaft or at least a pilot shaft or somethign long enough in the pilot bearing/bushing before trying to take the flywheel off the crank with that style bellhousing be it early six or V8 as those 40 something pound flywheels can come down on top of you real quick and hard and the ring gear leaves a hell of a mark on your arm or face. I packed marks on my arm from one for about a year back 4o something years ago.
261 has a long shaft water pump, the 235 is short. The 261 has a larger pulley for better cooling. There is a conversion to a short shaft pump with the larger pulley. Inventory for them has been tougher in recent years.
All 235 and 261 engines after 55 have the long shaft. I spent a half hour researching part numbers and cross referencing to make damned sure that my answer was correct. The one in post 7 above yours, 54 235 was the only pressure oil 235 that had the short pump.
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