The Stovebolt Site Forums The Shop Area Engine Shop My 261 build and discussion thread!

wolfcub, can you post any pictures of what your seeing on your engine? We want to help. Don't give up!

OK just looked over the block again on the left side and see no other numbers but it does have a number on the other side under the intake area. Looks like D 17 7. It has no numbers on the inside of the block if that was ever a possibility. If it helps im sure this block was from a Canadian vehicle.

Number 1

Number 2

Number 3

Number 4

Can you post a link to a photo of the engine serial number?

Can you post a link to a photo of the ledge/boss on the block, rearward of the distributor, where the Engine Serial Number is normally found?

Can you post a link to a photo of the top of your head (driver's-side rear quarter of the head), with the valve cover off? A date code should be near the valve cover "seat" between the 4th and 5th cylinder valve springs.

A replacement head made in 55-57 might have come without any engine serial number; or, maybe the replacement block might have come with the plant and month codes. The evidence for this suggestion/guess is that some people have shown photos of engine codes with different sizes/types of code letters/numbers.

Oops, I did not see your post when I refreshed this page, this morning.

I also apologize for not catching the Canadian ancestry of the engine.

Your links to photos may help others in helping you ID your engine.

My Canadian 261 doesn't have those numbers either.

nice to know im not going crazy and blind..........

Don't want to get in a [censored] contest with anyone, but when I purchased my 261 from a wrecking yard, it was a .030 engine. However it was frozen from sitting in the yard. It was bored .060 to clean it up. The head did Not have the steam passages drilled, I drilled them. Have had no problems with the engine.

I think you will be alright with upper end parts as long as you stick with pre-1958 parts. Inspect each part against the old one, and generally you will be fine.

If you drill out the restrictor fitting a bit and use a pinched off rocker connector the 1959-62 rockers will also work fine.
As far as 235 verses 261 rockers, I would not worry about that. The difference is the vent hole location. It may be in a slight different position, as the 261 truck rocker looks like Chev wanted to direct a little more oil over to the valve. For low to medium work load that will make no difference.

Picture #2...W86502....from just what I can see it looks like it may be on the pad behind the distributor?? Can that be the engine serial number?

OK so im going to start getting back on track with my build but just before i start i have a few more questions.

I was leaning towards sending the engine out for the full rebuild but im thinking i want to do it myself because im bored. The block would be sent of for the machine work such as boring, milling and installing the cam bearings.

I have been reading lots of other posts and web pages about rebuilding engines and not too many mention anything about checking the con rods for straightness as described in the original manual. Why does it seem that this step is almost always non existent in rebuilds?

A good machine shop will still check them. Most folks these days...let the shop do the basic reassembly. Some of us(fussy old farts) like to check and fit things ourselves. Ask. The shop that does the work should be happy to check the rods. Should include straight and out of round caps as well. I got this lesson on the very first engine I ever rebuilt. The Crank had been turned 10 under. The bearings I got were "standard". That rebuild did not go well. Plastigauge has been in the tool box ever since. Things you learn at 16 with very limited dollars stick.

So i picked up two of the engines he was selling. He decided to keep 2 for himself. One i got was recently rebuilt and the 848 head looks mint! Im going to take it apart anyways and clean it up to remove any possible contaminants and if it looks perfect i will use it in my build. The lower blocks i got have the side engine mounts so that gives me the opportunity to use that as a sexy mounting point for my spin on filter bracket. The block of the recently rebuilt one is 30 over and all the internals look brand new other than the missing crank. The rebuilt one was sitting because it spun a rod bearing.

Just to make sure but all the 235 and 261 cranks from 55 to 63 are the same right?

I think what i want to do is take that 1960 block that was recently rebuilt and still have it redone. Im not 100% sure if the rods or anything else might have been tweaked when the bearing spun. I will have it bored over to .040 as the pistons say 0.30 on them now. I will remove the cam and see what condition the journals are in then get a new cam from delta like what i have in my 235. If the cranks are for sure the same i have 2 spares that i got out of some recently dismantled 235 engines.

It looks like all 6 cylinder crankshafts were the same from 1954-1957. Maybe someone has a newer parts book to confirm all the same up through 1962?

235 cranks are the same from 1954-62. 261 cranks are the same as 235's.
A 1953 PG crank is also the same, although the clutch pilot bushing hole is smaller. That is because a pilot bushing was not used with a torque converter.

Getting a bit more things done on the 261 build. Ordered some larger intake valves today from Tom L along with another thermostat spacer for the heated intake. Had a long conversation with him regarding his carbs and bulldog cam. He is 100% certain that the current 32/32 cw carbs Im using now on mt 235 will be fine for a street 261 build up to 4000ish rpms. No need to move to the larger 32/36 units. Going to take the newer 261 block in this Saturday to have it inspected and cleaned.

Are the 32/32 cw carbs the 740 carbs?
There is also a 32/34 version (besides the 32/36 version).
http://www.classicgoldwings.com/forum/viewtopic.php?t=6892

Those 32/32 740 carbs were insufficient at over 2500 rpm on my 261 (bored .060).
They were excellent (responsive and efficient) carbs in every other regard.

When I told Tom this, he asked me why I bought them for a 261 (he said they were for the 235). I told him that I bought them at his suggestion.

I now have much more responsive (and adjustable) 2-barrel Holley on my 261.

Wonder whats going on then. He was very instant that the 32/32 units would have no issues what so ever and said the other larger ones were if you wanted to upgrade your single carb only. Once he tossed that one into the equation i got all mixed up as i thought even a 32/36 was smaller than a stock single.

I asked him because i have seen a few post up that the 32/32 units were not large enough. What Holley are you running and what intake?