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Posted By: Matties Looking for 261.. maybe?? - Sat May 09 2020 07:39 AM
Hey BC brothers and sisters. Hope you are all doing ok in this crazy world... What a nutty time!

So long story short, picked up a solid running 292 a few years ago with the eventual plan to build it for my 52 3100. I cant wait to do this, but the more research I put into it the more expensive it gets to even just drop it in. Still the long term goal, but in the meantime I had a crazy idea of swapping out the 216 in there for a 261... This seems like it would be a great little boost to daily driving fun, and mostly bolt right up to the stock 216 running gear.

a- Am I correct with this assumption that I can drop it in, using the existing trans and intake/exhaust manifold?
b- Anyone in BC have one they would be willing to let go? I'm in the Lower Mainland.

Thanks and stay well!
Matties
Posted By: tclederman Re: Looking for 261.. maybe?? - Sat May 09 2020 12:40 PM
a- Am I correct with this assumption that I can drop it in, using the existing trans and intake/exhaust manifold?
b- Anyone in BC have one they would be willing to let go? I'm in the Lower Mainland.

a. you are correct; almost: you will need to relocate the water pump (made by Pre '68 Dave [chev235guy.blogspot.com]). And, you might have to swap the "front mount plate" from your original engine, if the 261 used side front mounts.

b. place a Want Ad for a 216 in the Swap Meet
Posted By: sstock Re: Looking for 261.. maybe?? - Sat May 09 2020 02:28 PM
Last year, I almost gave up on finding a good solid rebuilder 261. In a last ditch effort, I looked one day in ebay and found one an hour up the road (Marysville Washington), complete long block and stock bore too, even had the larger correct rochester B carb. I've been buying lotto tickets since to no avail, but I did get lucky once so keep looking.
Steve
Posted By: John Milliman Re: Looking for 261.. maybe?? - Sat May 09 2020 03:54 PM
Correction -- You *could* use your 216 intake manifold .. but you shouldn't unless you want to choke it to death. The 261 needs the bigger carb/increased airflow, so use the 261 manifolds (or at least the ones from a 235) so you can use the bigger Rochester carb in place of the ole Carter W-1 smile -- a great carburetor (and one of the first inductees intot he Carburetor Hall of Fame, if I remember correctly -- Jon the Carb King can update us that that ), but too small for a 261... unless you use three of them wink

You don't have to relocate the water pump, or get a different front plate/motor mount if you find a '54 mold 261 (check out the conversation in this discussion about 261's

Also, read the Tech Tip (in the Tech Tip section) about rebuilding a 261.
Posted By: Hotrod Lincoln Re: Looking for 261.. maybe?? - Sat May 09 2020 05:17 PM
I'm still working out the logistics of building a 260 cubic inch engine with a 216 block and cylinder head- - - -the ultimate stovebolt "sleeper" engine!
Jerry
Posted By: Prairie Dog Re: Looking for 261.. maybe?? - Mon May 18 2020 05:52 PM
On a similar subject can anyone tell me the pitfalls of swapping out a 235 with a 270?
Posted By: tclederman Re: Looking for 261.. maybe?? - Mon May 18 2020 08:30 PM
You probably should have started a new post, Prairie Dog.

Welcome to Stovebolt.com.

"swapping out a 235 with a 270"
1. Into what make/year truck?
2. What year 235?

The later 235/261 engines have a water-pump that "sticks out" further that the earlier 216/235 water pumps.
This can be remedied.

Look in Tech Tips regarding engines.
But feel free to keep asking questions.

In each new thread/topic/question, be sure to indicate the Make, Yewar, and Model of your truck (and, describe pertinent modifications, if any).
Posted By: Green_98 Re: Looking for 261.. maybe?? - Thu Jun 04 2020 07:09 PM
I swapped a fresh built 261 in place of my 216 last summer, made a nice upgrade, but of course, you're still limited by transmission, rear end, and suspension limitations, so the truck will still drive essentially the same, only with a decent boost in HP and torque. Still nothing to get just overly excited about, in my opinion.

If you do find a 235 or 261, be sure to:
1. With 55 or newer 235/261 block, use the 216 short-shaft water pump (and the water pump adapter plate that can be found on ebay)
2. Drill the front of the block for the front motor mount
3. The 216 bellhousing may have to be used


Just a couple things that I remember from my swap, I know others will have more things to consider if you go that route.
Posted By: tclederman Re: Looking for 261.. maybe?? - Thu Jun 04 2020 11:11 PM
Excellent advice , Patrick

Here is a slightly emended version of your list:

If you do find a 1955-2nd series or newer 235 or 261, be sure to consider/adapt-for:

1. With 55-2nd or later 235/261 block, use the 1955nd or earlier 216/235/261 short-shaft water pump (and Pre '68 Dave's water pump adapter plate [chev235guy.blogspot.com] that can be found on ebay)

2. Drill the front of the block for the front motor mount:
Tech Tip 1, and, Tech Tip 2

3. The 216 or pre-1955-2nd 235/261 bell/clutch housing may have to be used to match rear motor mounts (which changed in 1954 and changed later.

Also, the clutch-assembly must have matching/compatible parts:
- diameters of clutch plate and pressure plate
- pressure-plate attachment to flywheel bolt-holes line up
- release/throw-out bearing matched pressure plate
Posted By: Sedgewick Re: Looking for 261.. maybe?? - Sun Jun 28 2020 08:56 PM
Tim - are you saying the 55 and earlier 235 water pump can be used without adapting the block as per Dave's adapter kit? I have a 235 in my 49 and it was done by the PO. I believe it is a 1956 era 235 and the fan blade is about 3/16" from the radiator. Its scary although I have been running it that way for 22 years.
I cannot change a fan belt if I break one. I carry a pair of nylon panty hose in the glove box in case I get stranded. At least that is what I told my wife! The motor mounts are solid but I do know that one day I will have to reconfigure the situation.
I am not confident enough to drill and tap the block for Dave's adapter
Posted By: tclederman Re: Looking for 261.. maybe?? - Sun Jun 28 2020 10:20 PM
"Tim - are you saying the 55 and earlier 235 water pump can be used without adapting the block as per Dave's adapter kit?" "Sedgewick"

I might have stated/phrased this incorrectly: (?)

"With 55-2nd or later 235/261 block, use the 1955nd or earlier 216/235/261 short-shaft water pump (and Pre '68 Dave's water pump adapter plate [chev235guy.blogspot.com] that can be found on ebay)"

" . . . a 1956 era 235 and the fan blade is about 3/16" from the radiator . . "
That block/engine would need Dave's adapter and an earlier style (higher-mounted") water pump.

Your 1956 engine would need the adapter and an earlier style water pump.
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