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Author Topic:   exhaust question
Dirt Maniac

Total posts: 169
posted April 17, 2004 04:21 PM  
Hey girls and guys,

I got to run stock exhaust mainfolds on my small block chevy. I want to install larger exhaust pipes than the 1 3/4 stock exhaust and put the summit X assy on it. What is the largest size pipe I can put off a manifold.

Hope someone can help me out here.


redneck racing
Dirt Forum Champ
Total posts: 860
posted April 17, 2004 04:45 PM  
This may be crude but this is how I did it when i ran stock exhaust manifolds. Take the stock sized pipe that fits the manifold go to your local parts store and get a exhaust coupler to fit the stock pipe and the biggest size you can get for the other and weld them together. I ran the stock pipe into 3" exhaust and it worked great. Hope this helps. Eddie

Dirt Forum Champ
Total posts: 640
posted April 17, 2004 07:49 PM  
when I worked at an exhaust shop I was able to neck down 3" pipe to 1 1/4 and then flar it to excypt the stock flange so 3" was not a problem I would find a good exhaust shop


Dirt Forum Racer

Total posts: 90
posted April 18, 2004 06:07 PM  
brezinski makes a really simple coupler to go from stock manifolds to 3" exhaust

Dirt Maniac

Total posts: 169
posted April 19, 2004 07:41 PM  
thanks guys,

another question same line... there's a flapper valve on the way out of the manifold. I'm sure its for some heat thing for choke or emissions. Any ideas on getting it out of there? I can probably drill it out and then weld up the hole, but if y'all have any ideas I'd appreciate it.

Winland Racing
Dirt Maniac

Total posts: 122
posted April 20, 2004 12:27 PM  
Just torch the flap on the inside, I believe the through hole will still be blocked by the rotating arm, just leave that in there. I have ran it that way for years with no problems.

Dirt Roller

Total posts: 18
posted April 20, 2004 05:34 PM  
FYI If you can find a set of the old center dump manifolds, I've heard they flow better.

Dirt Maniac

Total posts: 169
posted April 28, 2004 08:31 AM  
I have a set, they won't fit because of the crossmember, I think. I'll try them later today.

Dirt Forum Champ
Total posts: 517
posted April 28, 2004 11:06 AM  
My crossmember was notched in order to run the center dumps. From what I've heard they are the best stock ones you can find. It may be alittle more trouble notching the crossmember, but I think it will be worth it.

Smith Racing Team

Dirt Maniac

Total posts: 118
posted April 28, 2004 01:03 PM  
We have just installed center dumps. We had to move the engine back until #1 plug was inline with the ball joint. Then we had to notch the crossmember to make room for the fuel pump. An awful lot of work but the big benefit is a little more rear percentage on the scales.

Thanks, Rob
(Cold Blooded Racing)

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