Stock Gm exhaust manafold, altering!

rooster · July 15, 2005, 06:32:05 PM

Is it possable :?: I was thinking that if I could make a few cuts on manafold that I could then heat it and bend it a few degree's, then weld up. What kind of life could I expect from it. anyone done it?

model a vette · July 15, 2005, 07:04:30 PM

A stock manifold is cast iron - not bendable! It can be cut to section it and MAYBE rewelded. There are special welding rods to weld cast.
The problem with welding an exhaust manifold is the extreme range of the operating temps.
What are you trying to accomplish?

rooster · July 15, 2005, 07:25:19 PM

Quote from: "model a vette"A stock manifold is cast iron - not bendable! It can be cut to section it and MAYBE rewelded. There are special welding rods to weld cast.
The problem with welding an exhaust manifold is the extreme range of the operating temps.
What are you trying to accomplish?

I need to move the dump end toward the side of the block a few degree's, dont need much. Got some steering suff in the way. Im thinking it would bend some until it brakes.

model a vette · July 15, 2005, 07:47:25 PM

It won't bend at all! It will just break!

Would you have room for a rams horn manifold that points the center dump forward?

How about a passenger side one, similar to what you have, that dumps forward of the first cyl when on the drivers side?

A stock '55 265 manifold dumps straight down between the first and second cyl and the two bolt flange is very close to the log of the manifold.

kb426 · July 15, 2005, 07:55:15 PM

Years ago, one of my friends and I installed a 396 in a 67 gto. The manifold we used had the outlet in the wrong place. We sawed it up and brazed it back together with an O&A torch. About 2 weeks later, I saw a chexy pickup with a factory 396 with the manifold we needed. If the manifold is not full of lead deposits, it is brazeable. Just bolt it on an old head to keep it flat.

rooster · July 15, 2005, 09:02:56 PM

The Ramhorn is sons first choise, but going toward the back. It looks like it could be cut off then rewelded to different position, might take two ramhorns to make 1. Notice in the picture that the steering box had to be moved about a inch just to take picture.

thanks for the idea about using a old head , that should come in handy if we do this.

The pictue in the starting post will work but requires cuting some of the body support in that area, it also places the ex pipe in the master cyclinder area witch is crowed allready.

model a vette · July 15, 2005, 09:43:30 PM

Would there be enough room to run a pipe forward of the motor mount if you used the rams horn with the dump pointing forward? There is a stock one like that that came on early ChevyII's with V8s and some other Chevies. It would take some creative routing of the pipe but pipes are easier to bend than cast iron!
It seems like you have plenty going on near the firewall!

enjenjo · July 15, 2005, 09:44:50 PM

A 265 Manifold will fit, and clear everything. You do have to get a bit creative on the head pipe, it bends forward and down to clear the mount, then bend back and up to clear the draglink, then bends down again, and angles in toward the pan to clear the steering box.

As was said, you can't bend cast iron, but you can cut it off, remove an angled section, and reweld it. I use Certanium 702 welding rod. Expensive, but it welds like butter.

Bib_Overalls · July 15, 2005, 11:51:36 PM

I've got a SBC driver's side manifold that exits down from the #7 cylinder.

It is yours for $5 and shipping. It has some air injection ports that will have to be tapped and plugged.

Email me if you are interested.

rooster · July 16, 2005, 12:35:17 AM

Quote from: "Bib_Overalls"I've got a SBC driver's side manifold that exits down from the #7 cylinder.

It is yours for $5 and shipping. It has some air injection ports that will have to be tapped and plugged.

Email me if you are interested.

Bib, does it look like the one with the guard on it? GM# 28173!

Its the last one I have to try, but cant until a chunck of firewall is removed, I kinda like it under the plugs arrangement plus it looks to clear the nut on the steering arm, with the box in its stock location. Those air things a ugly, I dont think JR will go for it unless I put them on backwards and stick pipes on them straight up in the air. LOL

Thanks for the offer though!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Phil1934 · July 16, 2005, 06:49:24 AM

Just angle mill the mounting surface. You may need to spot face the bolt holes at the new angle.

Pope Downunder · July 16, 2005, 07:59:22 AM

Quote from: "rooster"Is it possable :?: I was thinking that if I could make a few cuts on manafold that I could then heat it and bend it a few degree's, then weld up. What kind of life could I expect from it. anyone done it?

It will not bend!
On my pickup, I had a similar problem with the RHS Ramshorn. I worked out what needed to happen, and mad a weding jig to hold the flange in the correct spot, and give clear access all round. Then, I cut the end right ff and refitted the gap, and shamfered it right back.

I was going to stick weld it, but a fellow I knew said; yes, that will probably be OK, but he felt it was better to metal spray it. I was a bit sus; but I thought it wasn't a great risk. He was using it regularly at his work for construction plant repairs, so he knew how to operate it.

We used two Oxy sets; one operating the metal sprayer, and one with a rosebud tip to get, and keep the part cherry red. He did the spraying. Anyway, after it was done I dressed it back, and it looked like original metal.

It's been on there 5 years now without a problem.

GPster · July 16, 2005, 08:53:24 AM

Of course this is not the way you're thinking but think about a rear-steer rack and pinion that has both steering arms connected near the center of the rack. That may get a lot of that monkey motion out of the way. The 265 monifolds that Enjenjo was refering to are '55 and '56 manifolds and we did use them but on a lot of applications we were still using front engine mounts. The side mounted engine does make things a little hairier. An old trick. Not only find and old head to bolt the manifold to if you go with the welding but build a little fire in the back yard and put the pieces in the fire so that they ALL get hot. One of the problems with welding cast iron is that if it only gets hot at the place you're welding it will crack somewhere else due to the temperature difference of the metal. Got that from an old timer that repaired the crank web on a 426 "Hemi" with a home welder driven by a Model "A" engine. GPster

Bib_Overalls · July 16, 2005, 01:07:33 PM

Well, I got the manifold out and I looks a lot like the one you already have. So sorry.

Understand one version of the LT1 driver side manifold exits between #5 and #7 and points down and back. If it fits it would flow better than a 305 manifold.

48ford · July 16, 2005, 02:15:15 PM

Quote from: "rooster"Is it possable :?: I was thinking that if I could make a few cuts on manafold that I could then heat it and bend it a few degree's, then weld up. What kind of life could I expect from it. anyone done it?

I looked at my junk pile and can't find what I want.
I seen a small block manifold that kikes in closer to the block(may be off an i-rock or monte SS,it's out there I seen one.
can you use one off the other side and dump out the front or is that worse?
I also remember chevy used a ram horn on an early 60s truch that was tilted front not streight down.
block hugger headers?
Trying to help
Russ