Originally Posted by
Iraq&Roll
But generally, with GT40 heads once you have them machined, ported, new springs and guide plates are not worth the investment compared to a decent aluminum head.
Completely true. Had I not got them for a great price I would have went with an AFR or TFS head. I made that mistake with a set of Vortec 906 heads, by the time I got done with machining, seals, springs, retainers, and locks, I spent the same as I would have on a set of aftermarket aluminum heads.