[Formula jg]

I believe there is a post in the archive which references header comparison test done by the Hand's. If memory serves me correct, the 1 5/8" was very competitive with the larger size headers tested.

I think?

[goquick]

You are also talking about a much heavier car vs. the Firebird. I trried it, and there is a serious difference in performance. Something else to consider; With marginal pump gas quality, the engine with the larger headers will run cooler because the not as much heat is kept in it. This can also lead to a less likely chance of "ping" with the larger headers. I've seen it on my own stuff.