this is why I started the thread on the Race part of the Forum Speedmaster Pro Comp heads.. I wanted to gather more information as I was scouring the internet for any information and a lot of it was the Chevy people talking about them and other people just perpetuating false information and hearsay... From everybody that chimed in on the thread and that goes from engine builders to Serious drag racers there doesn't seem to be a big problem with them... Of course there isn't anyone that will tell you that it's great to bolt any head on straight out of the box and that's goes from Speedmaster, Edelbrock, to trick flow...