I ran an 11.0 at 129 with 100% stock un-ported headers and put down 579whp with them in my old Blue 86 TType. (cruzn57) in CA has the car now and with some tuning and a couple other tricks he put down 620whp (Ironheads/TE-45A /Comp 212-212) combo.
Anyway's, right now I have Poston's headers and couldn't be happier with them. Spool up seems a lot more responsive/quick too. Just couldn't pass up the deal on them. $50....Had a crack in one of them, and just ended up getting both of them reinforced everywhere, just like my stockers on the Blue TType. $50 to weld, so $100 for everything. Not too bad..
probl good for a few extra horses, but no signifigant gains. may spool a little better with a larger turbo.Many other upgrades to throw money at that would make better improvements.My combo made 509rwhp and i still have the stockers. just my .02