I need some help deciding on some headers. They are for a 5.3 with mildly ported heads milled .040” with a tr224 cam. This motor is going in a ’67 Camaro with a 5 speed manual and am going with the Dynatech swap headers with 1.875” primaries. My question is, should I get 2.5 or 3” collectors? I’ve searched and cannot decide. Thanks for the help.

 

3in ftw!

 

3 inch!!!

 

Sounds unanimous. I wasn’t sure if 3” was going to hurt velocity on a 350-375whp motor. I was planning on running true 2.5” duals. Guess it’s better to step down gradually anyway. Thanks!