[76 Badbird]

I am looking to put in a new header back ehaust system on my 76 TA. I have a 455 with the following:

.30 over bore
Butler street strip heads 6x milled to 94cc
041 cam
1.65 HS roller rockers
TRW pistons
balanced rotating assembly
RPM manifold
Holley 770
Holley blue pump
Tri-y header
TH400 with 2500 converter
3.42 gears

I am looking at a Pypes system with an X pipe. What I am not sure of is should I go 2 1/2" or 3". I have heard that an exhaust too large can hurt your performance just like one to small can. I might even go with a little bigger cam so I i am borderline on the size I would want the bigger one right?

With this combo what would be some suggestions. This is a street strip car that is only driven on the occasional weekend.

[Beebe]

I was in a similar boat as you . Similar combo , similar car. I opted for the 3" due to possibilities later. I doubt you will notice the loss of low end without the backpressure with the 3" system.

Im glad I went bigger, now 10 years later, my Torq Tech 3" still looks great and is ready for the stroker / head / No2 that I keep dreaming about .

[quick67bird]

I have a first gen firebird and when I was doing my exhaust all the machine shops told me 3" was too big, but I stuck to my guns and I am glad I got the 3" exhaust. The exhaust has been behind a 350 pontiac that ran 13.42 @ 106 and a 455 that ran11.65 @ 115.

Robert

[DiamondJim]

Another option is to reduce from 3" to 2-1/2" in the X. That makes sense if you think of the cooling effect and the space required by the exhaust gasses. There would be very little difference between this and a full 3". -Jim