[JackMonkey]

I have a 3" Pypes Dual system for my '68 Firebird. They now have a 2-1/2" Stainless system available. I can trade up to SS for about $50 due to restocking fee. I don't know what I should do. I like the fact that SS will last longer but will 2-1/2" be sufficient for future upgrades? (ex. 462 stroker)

68 Firebird
Dougs Headers
406 block
E-Heads
Jack Gaydosh cam (don't know specs)
RPM manifold
Holley 780
TH400 w/2400 stall
10 bold rear, probably go with 3.55's

Car will be 85% street, 15% track with NOS?

Any input is greatly appreciated.

[Speargun]

The common line of thinking is 2 1/2" for under 500 hp and 3" for over 500 hp. Based on what I've read here, you might not like the ground clearance issues with the 3" system.

Here are a couple exhaust links that might help.

http://forums.maxperformanceinc.com/...d.php?t=493094
http://forums.maxperformanceinc.com/...d.php?t=491175

Good luck.

[Ron H]

I never had problems with clearance and the 3" system in my 68. If you are getting work done by Gaydosh ask him what he thinks. I am sure he will say 3". The aluminized pipe will last along time.

[Ccass]

The systems are still not available fully in stainless yet. Probably won't be until late March. If you take care of your car like most classic owners do, you will not have a problem with aluminized. It will last the life of that car. Pypes has a lifetime warranty. The 3" stainless is even further behind that. Your combination does not warrant 3". Low 12's high 11's is perfect for 2.5" as long as everything is mandrel bent. 3" also creates additional clearance issues. Stick with the 2.5" aluminized system.