Heres the deal, I have a mildly built GSR motor. The comp is about 11.5:1 and

I’m also running pro 1 cams. The head has no porting of any kind. Its about the

header and exhaust I’m concerned. I was in the market for a nice/decent header

so I decided to go with the rage tri-y standard. Then I got a wicked deal on the big

tube version that I just could not have passed on. I’m now thinking that this

header would hurt my set up but how much?? My original plan was to get the

standard version and put 2.5” exhaust with no cat on it, the car has 2.1/4” exhaust

now with a cat. So my question is should I still put on the big tube header and run

the 2.5” exhaust with no cat(I’m thinking too much of a free flow) or to keep some

of the needed back pressure keep the 2.1/4 on it. What kind of gain or loss would

I be looking at?

Thanks

 

Bump for some advice!!!!!

 

Don't bother putting the big tube on. You can make the same amount of power with the narrow. Just sell it and make a profit. And go with the 2.5" all the way

 

with that header no cat and 2.5 catback, you might lose some low end but you will make it up on top end. this is my advice . do what you want to do. try both setups see what you like or not.