I am wondering how everyone is getting a smooth transition from the exhaust runner to the rectangular flange. I am working on making a manifold and want a smooth a transition as I can get. My first thoughts are to get some DOM tubing and make a mandrel and press/hammer the tubing to shape? Anyone done this? Does someone already do this with relatively thick tube/pipe? I have seen the thin 16 gauge transitions but nothing with at least .100 in wall.

 

In addition to that, do yourself a big favor and use a torch.

 

Well i just squished the tube down till it fit inside the flange. Then i tack welded the edges and used an air hammer to stretch the tube into shape. On the straight section it was super easy but on the center of a bend it gets kinda tricky.



Allen

 

Yeah, I figured I would need the oxy fuel to get it to shape. Is this how everyone else does it?

 

I put it into a vise

 

I vice will work just fine. Take a left over (drop) piece and try it first to get a idea of what you need to do, then go at it.

 

AHH YES, the art of metal working is coming back, who woudathougt, anywho 1st do the best you can on making the manifold ,vise it, heat it, hammer it, shape it, then smooth out the inside with carbide burrs as best you can , then send it out for EXTRUDE honing, finally have it CERAMIC coated inside and out, betcha nobody elses manifold will make anymore power than yours. Ron

 

You've got it easy with .100 wall. I foolishly decided to use 2" schedule 40 304SS pipe (3/16" wall). A torch, a vise, a big hammer and an anvil eventually worked for me.