Split Stock Manifold 1952 Chevy

Split Stock Manifold 1952 Chevy

I wanted to share some pics of how I went about splitting my manifold. At first I had considered Fentons but because of my aftermarket Oil filter, InnerLine, Fentons wound not work due to interference issues. I then bought a set of tube headers from Speedway but they too had several interference issues. With the tube headers the front header needed reworking to clear the oil filter. The rear interfered with the throttle linkage and the welded on bung for the heat tube pointed right out at the parking brake rod and would have needed to be relocated. Pic below shows the tube headers I had ordered and returned.



I saw several past posts on different forums about splitting the stock manifold and decided to give it a go since neither the Fentons or Tube headers worked out. I bought a 90° cast iron fitting at a local plumbing supply house in KC, Reeves-Wiederman. I took my manifold with me and held several fittings up to it, a 1.25 was the best fit with an actual inner ID of 1.75 in. I cut the raised lip of one side so it would hug the manifold a little closer and then welded on a 2 in. exhaust flange. I put the weld on the inside to hide it.





I achieved one big hole in my manifold with a bunch of small holes and a de-burring bit on my die grinder. I first attempted to MIG weld the fitting with standard ER70S6 wire for mild steel by preheating it and cranking up the heat on my welder. I put on several tacks but had lousy penetration into the cast iron. You could easily snap the tacked fitting off. I based this technique on another post I read on ChevyTalk.org and going with what I had. I talked to a helpful guy at a welding supply house (Welds Supply in KC, also give a quick thumbs up for Hohenschild in KC) and he gave me three options for welding cast iron.
1. Arch weld with nickel rod, nickel rod at $68/lb, minimum purchase, 1 lb (I dont own an arch welder).
2. Weld with special MIG wire he had in inventory, $35/lb, he only had it on 30+ lb spools.
3. Go old school and braze it with brass rod. Fortunately I just happened to pick up an oxy-acetylene set-up the week before on CL.

I hadnt brazed since a community college welding course I took over 10 years ago so I watched a couple of You Tube videos along with going with the advice I got. The one thing that was stressed the most was to cool the manifold slowly by either a welding blanket or packing it sand or oil dry.

Later, I did find a manufacturer that sells two pound spools of cast iron MIG wire: Crown Alloys Royal 44-30 Premium Nickel-Iron- Manganese MIG Wire. I never called and got a price but I saw on other forums it runs $30-35/lb.

Talking to a couple of welders, the ER70S6 MIG wire route was just wrong; the material properties just arent there to make it work. There are also many grades of cast iron along with cast iron cleanliness you have to consider. They said you may get it to stick but more than likely it's eventually going to snap off.













To split the manifold I cut a slit in the back and ground out a dish with my de-burring took to fill with brass. I cut , ground, and fitted a plate to fit tight inside the manifold to seal one side from the other. I then brazed up the slit in the back.







Heres some pics with the manifold back on the car. There was a little warpage which I think was from the result of trying to MIG weld it. It was a little high in the center but it bolted up and sealed without any issue.







For guys with a similar year, youll have to relocate the throttle rod to clear the new outlet. I cut the old rod off where the thin portion meets the thick portion. I bent a new rod out of stock material. I drilled a hole in the larger rod to insert the smaller one into, and then welded them together. I also relocated the throttle spring tab from being secured by an oil pan bolt by welding it to the original outlet pipe.





Continued below

 

I built the exhaust from mandrel U-bends I got from Speedway. I ran two 30 in. Smithys glass packs. I put in a couple of exhaust flanges to make it easier on the install and future removal. I used rod style hangers that I welded to the exhaust along with bending them under the exhaust tubing. I ran the exhaust under the axle. The pipe on the passenger side runs between the gas tank and spare tire well, the drivers side pipe I had to snake around the gas tank between the gas tank and leaf spring. I wanted to exit them under the bumper and a little closer to the center. I left the pipes sticking out about 6 in. Id like to find some nice pencil tips for them in the future. Since the U-bends were plain steel I went ahead and shot all the exhaust with some Rust-Oleum BBQ paint. The paint on the Smithys was crap, I ended up wire wheeling it all off and starting over.

















Splitting the manifold myself ended up saving some $$ but it still ended up being a fairly expensive and time consuming endeavor. Below is what I spent:
Two 30 in. Smithy's Glass packs, Speedway, $78
Five U-Bends, Speedway, $50
Seven 2 in. Exhaust Flanges, Speedway, $35
Four 2 in. Exhaust Flange Gaskets, Speedway, $8
Speedway Order Shipping, Speedway, $24
Four Exhaust Clamps, CarQuest, $10
Four Exhaust Hangers, CarQuest, $20
20 ft 2 in. Aluminizes 16 gauge Exhaust Tubing, Car Quest, $68
1.25 90° Pipe Fitting, Reeves Wiedeman Plumbing, $6
Brass Brazing Rod, Welds Supply, $3 worth
Welding Wire, approx 2 lbs, Welds Supply, $8
Two cans of Rust-Oleum BBQ Paint, Home Depot, $10
Total: $320

Some lessons learned:
If I were to do it over, I may consider stainless steel on the exhaust. Running mandrel tubing is time consuming, and I would say especially so when doing it with your car on jack stands. It just take a long time to make the cuts, fit it, tack it, try it out, and weld it up. I bet I had the exhaust and manifold in and out of the car 20 times. I took my time and ended up with no waste on my u-bends and only a couple of feet of waste on my exhaust tubing.

Secondly, I wished I had talked to more people when selecting my glass packs. The 30 in. Smithys ended up being a bit to tame for my taste. However, I did want something mellow with my kids and wife riding in the car so I guess I accomplished that. They have gotten better sounding as Ive been driving it. I may in the future look at putting cut outs and straight pipes around the glass packs to give it a mean sound when I want. Or, actually hooking up the lakers.

I shot a couple of videos to try and capture the sound. I sounds a little better in person but like I said, its pretty mellow:



And finally back on all fours after spending too much time up on jack stands.

 

The work and craftsmanship are excellent. I still prefer the spilt mainifolds for my daily drivers for the heat riser effect. I keep mine lubed up but did you know the factory and a few others had a mass production run in 1954-55 for the 235's? It even fits the 261's too. I have included a photo of a knock off from where I lived years ago.
Normbc9

 

Very good thread!! Nice work too. I was just thinking about this recently om a '54 so this is perfect timing. This right here is what the HAMB is all about! Thanks for this.

 

Nice work!! Sounded great to me on the youtube video. One question, do you think the divider plate is really needed? I have a stock split manifold I was gonna put on my 60 Belair this winter. It does not have a divider plate but I may add on if it is needed.
I did my own split exhaust on my 50 Chevy with a 250 6 cyl. It wasn't difficult but it seemed like a million trips back and forth from under the car!! Todd

 

this is more question than statement as i have only had one split manifold and that was 50 years ago---i thought you needed a 4/2 split to get it to rap---hardcore was 5/1 --isn't yours a 3/3 --even with a block off very mellow----price at the muffler shop included 2 mufflers 45.00--noise tickets 20.00 a pop---your work is very nice---much nicer than the muffler shop

 

Thanks! Everyone I've talked to says yes, a divider plate is needed to get the "split sound". I havn't been around straight sixes too long so I can't tell you the sound differance other than there is a "split sound".

I know what you're say about a million trips back and forth.

 

I've been told about the 4/2 split but with the siamese port on thier straight sixes I don't know how you would get a true 4/2 split with only two outlets. The only way I see this happening is sectioning off cyl 1 and 6 with thier own ports, bringing them together then cyls 2 -4 exit out of the center. A guy told me about this on another post. His technique may have a unique sound of its own.

http://www.jalopyjournal.com/forum/showthread.php?t=745498