Splitting a 216 while keeping stock heat riser?

I've searched and read, I think, pretty much every thread about it on here. But cant find any exact examples of a split 216 manifold while utilizing the stock heat riser. I think I have seen a few pics floating around on the interwebs, but has anyone here done it first hand or owned a car with one? I'm thinking about cutting my manifold right after the heat riser and taking about an inch then welding up the gaps and throwing on a new exhaust outlet. any info, opinions or advice will be greatly appreciated, thanks guys and girls?

 

You're on the right track ... leave the heat riser intact. Then, instead of cutting it in half, leave it in one piece. Add the dual side outlet as normal. Cut a slot in the back side & insert the blockoff plate you filed to a perfect fit & weld.

 

So your saying make a small incision right after the heat riser and slip in a piece of fabbed up metal and weld shut. then add the outlet as normal?

 

Right after? Right to the rear of cyl #3 is where the block off plate would go. The rear outlet will be centered (or close to) cyl #5.
I've done this a bunch of times and it works well.

 

you got any pics?

 

NOT mentioned yet is what I have had done to two six bangers.
Split the manifold 4-2 instead of 3-3 for cooler exhaust sound.
Eliminating the heat riser also increases noise...A good thing.

 

Back in the day I would take the intake off the exhaust. Then put the block in from the top. If I was you I would drill a hole in the plate before you weld it in. If not it is going to be real loud. To me it sounds good at 3/4 block.

 

real loud huh? I like where this is going

 

I was thinking of doing one for a 250. I like the idea of not cutting the thing in half to do it.
Good Luck!

 

It seems very straight forward, I just hope I'm not over looking anything. Oh well, guess I'll figure out that the hard way.

 

http://www.jalopyjournal.com/forum/showthread.php?t=334539&highlight=split

 

how i did it.....on a 250cid., but similar on the 216´
http://leaded.sitesled.com/manifold.html

 

I should have said it will be real loud with steel pack mufflers, that was before glass packs. It will be loud with any straight through mufflers. For a different sound use to different kinds of mufflers.

 

Yeah, I keep reading about the one straight and one through a glasspack. I already have a glasspack on now so I'll probably keep it on and throw a straight on the other and see how I like it.

 

You're not going to split an exhaust manifold for a 216/235/261 4 and 2. The port layout is 1-2-2-1, so it pretty much has to be split 3 and 3.

 

This is one split in the old days. My buddy loaned it to me for a couple of weeks when my stock manifold split the wrong way, lol.

Stock, unnatural split, a.k.a. broken...


Top- pure junk recent split piece. Extra outlet added and divider in center. Immediately broke after initial use.
Middle- righteous vintage split piece done the right way.
Bottom- the venerable Fentons still made under license by Patrick's.



Close ups of righteous vintage split manifold. Note heat riser and spring still in place and operable...





You have to be very careful welding old cast iron. Contamination from exhast and rust will be prevalent on 60 year old exhasut manifolds. Its hard to get good welds on these pieces. Its really best to take it to a professional for best results. Hope this helps!!!

 

A titch OT, which I'm sorry about...but I'm running Porter Steelpacks on my Chevy 292 running 3-3 split manifolds (from Langdon's)...it sounds farking awesome. Dunno about the one straight and one muffled deal, but this is certainly loud enough to scare people by about 4 grand, and sounds good no matter what.

Odd question..why split the stock manifold? Conversely....why not find a set of old Fentons?

 

I think one of the best reasons for a split stock manifold is if you're going for a "back yard build" type of car/truck. Back then, not everybody could afford a set of Fentons. So they split their own.

As far as sound for the earlier stovebolts (216, 235, 261), my vote goes to Fentons. My exhaust sounds so nice it makes my pants tight. Let off the gas or in between shifts and its sweet sweet music!!

 

no $$, gotta make it myself, plus what do you do about the heat riser with fentons?

 

That's what the two pipe plugs in the headers are for; you bolt a flat plate to the bottom of the intake and run two 1/2 inch copper tubes to it.

 

I think that this split manifold is the coolest! Its part of an engine package for sale here on the hamb but this is how I would try to do it....

 

another option is one of these.. its a factory GM split manifold for the 53-55 corvette 235... I picked up this one for $150! I need to weld half a tab on but... no biggie plus it was cheaper than fentons...

 

Try to find another set for $150. That is an anomoly.

 

believe me I know it was a gift from above! I was just at daytona for the turkey run and didn't find crap for the inline motor's... I have more time than money so searching is no problem.

 

Today, that's common. But please remember not many of us could afford the $30 they cost in the early '60s, but $5-$7.50 would get the manifold split on just about anything you carried in the door.

 

Why did it break? what broke?

 

Well search no more! I've got some killer stovebolt dress up and hop up stuff to get rid of so I can get some Cadillac dress up and hop up stuff I need, lol. A vintage polished triple offy intake with Carter W1's and polished air cleaners would look killer on top of that vette manifold. I'll have a Wayne set up for sale soon too.


http://www.jalopyjournal.com/forum/showthread.php?t=535291

 

The pic here is a pure stock manifold. It just cracked in half with age/deterioration. This is the kind of split manifold nobody wants, lol.







The top manifold in the second pic in my post was a stock manifold recently split by a guy who then would sell them. The extra outlet broke off on the first one he sent me during shipping. It also cracked around one of the runners. This was before running it. The replacement he sent lasted about two days before the center divider came unwelded. The mounting surface was also not true.

These are some of the problems that come from welding old contaminated cast iron. The heat from welding can warp the manifold causing exhaust leaks or weaken the material which can cause cracks. You can get poor penetration of the welds due to all the carbon built up from years of use prior to welding it. This was not as much of a problem "way back when" when these manifolds were newer and in better shape.

From what I've been told by those much smarter than me, it is very difficult to weld cast iron. Especially old cast iron exhaust manifolds. Talk to a real pro on this subject, not just a diy kind of guy. They will give you a litany of reasons why its hard to successfully split an old used cast iron exhaust manifold.

I wanted a stock split manifold for my 261. But my advice is that unless you can find one split "way back when" or a vette unit, go with the Fentons. They still have the provisions for heating the intake and will not leave you unhappy because they are not going to break.

These issues are not just limited to the chevy manifolds. A buddy has had some of the same issues with a recently split buick straight 8 exhaust manifold.




***EDITED TO ADD***

Don't get the wrong idea. I'm not saying it can't be done. I'm just saying its difficult to do it correctly. Some super pro was explaining it to me and most of the welding tech was way over my head. But something about an oxygen free enviornment like a vacuum was needed to do it right, lol. Seriously.

 

Don't get the wrong idea. I'm not saying it can't be done. I'm just saying its difficult to do it correctly. Some super pro was explaining it to me and most of the welding tech was way over my head. But something about an oxygen free enviornment like a vacuum was needed to do it right, lol. Seriously.

I did my first one at 16 years old. no money, I did not know any better, so I weld it up with gas welder and fence wire. Some one had told me to cool it very slow. So I covered it with asbestos. Did a few more for friends after that the same way. Never had one break. I would not do it that way today, but we have better rods, welders and such today.

 

I have done a few. See here:

http://www.stovebolt.com/ubbthreads...E+SPLIT+MANIFOLD+INFO"&Search=true#Post470651