The Stovebolt Site Forums The Shop Area Engine Shop A 3836108 exhaust split manifold

This is on a 261 I just bought.
The engine was in a 1960 1 ton factory 4x4,
USA made, most likely.
Regular intake manifold.
It turns.
I’m planning it for the ‘54 3100, to replace the rattly ‘59 235, eventually.
Does anyone know if this engine could have been sold with this split manifold ?
Engine has the number GM 3769925.
Under the captain’s bars : CONN 3. 7 11 5
No number on the pad by dist.
On top of the head , driver’s side 3836850. GM 5
On top of the head , pass. side. B 59 848
850
Again, I am calling on the much appreciated expertise of you folks !
If it turns out this engine is re-buildable , I’d hope to pair it with the 5 speed.

That looks like it was broken in half.

That one looks like it's been modified, but there was a factory split exhaust manifold for the 6 cylinder Corvette, and thousands of them were sold by Chevy parts departments and used on 235 and 261 engines. If you've got a bit of experience welding cast iron, any exhaust manifold can be split, but it's a little more complex than just adding a second pipe flange. A baffle must be inserted to almost, but not quite block off the flow between the two pipes. That approach, even if a stock manifold is modified and the OEM manifold is not used, is far better than the "Fenton" knockoffs that eliminate the heat riser.
Jerry

Steelonsteel,

Your engine casting number 3769925 indicates a 1960-62 Truck 261 (261 confirmed by the "Captains bars" on side of block behind where the starter mounts). The casting date code 7 11 5 I believe indicates "July 11th 1965". That should be accurate as that blank engine serial number surface being left unstamped indicates the engine is probably a later cast service replacement (others will chime in to clear that thought up).

The head casting number 3836850 indicates a 1956-62 Truck 261 (with the large temp sender hole).

The "split exhaust manifold" casting number 3836108 (seen in one of your attached pics) ID's that piece as a factory 1953-55 Corvette 235 exhaust manifold (see screenshot below from a known Corvette info site). It was commonly used to upgrade engine performance back in the day. That piece is quite a nice find as they are very sought after.

For a bit more info, check out this older thread about this manifold.

All around a fantastic good find!

Dan

Thank you all for the quick response.
So, I’m guessing this truck got an engine swap in the Sixties and
a Corvette exhaust manifold from over the counter added at that time. Maybe.
The truck reportedly was brought from California a ( To BC ) lot of years ago by a gold miner.
I will shortly strip the engine down and assess if that iron crack might be repairable.
Looks like a heat crack that’s open slightly.
Would be nice if I can use it!
Thank you all again for the attention.
Charley

So you have 3 engines now? That's good as some of these parts are getting hard to find.

Digging down thru the past posts, I found this article on Tim Lederman’s website published in May 1955 Hot Rod Magazine article on soupin' up the 261 cubic in Chevy engine I found very interesting and thought of Jerry immediately. It wouldn’t surprise me if he has already seen it before or even has a copy.

http://1954advance-design.com/Documents/261SoupThatChev/index.html

Don't toss that exhaust manifold...it is repairable with the right process. Have done several.

I seem to remember reading that article shortly after it was published. Back then, I was an annoying pre-teen kid hanging around Dad's race shop, but he built flathead Fords, not Chevy or GMC engines. The GMC 270s had lots of torque, and there were thousands of them available in surplus WW II military trucks. Their big problem was traction- - - -while they were spinning wheels coming off the turns, Dad's tight-winding flathead would be halfway down the straight, and his driver was getting set up for the next turn. His driver loved to "drift" the car through the turns- - - -chop the throttle once, then climb back into it and spin wheels all the way around.
Jerry

Yes, Gord, it’s fortunate for me.
I have the two 261’s and another one ( in the‘59 Pontiac) available.
And the 235 that’s in the truck.
Hoping at least one of the engines is in rebuildable shape!

Curt, thank you , glad to hear that it’s likely repairable!
I remember being told, ages ago, that you can heat cast iron to a dull red and weld with a torch, and then
cool slowly. Bit it seems that folks do it easier than that.

Jerry probably wrote it.

What a great article. I’ll have some more questions on the subject after I digest the article more.
Thanks for this.
Charley Erck