The heads are GM fastburns (210 cc intake runners )that are rolled a touch
. I had them for a class i used to run that required a 23 degree head . Out of the box they will support 500 hp . These have had some touch up in the way of polishing and severe duty valve installed . Quench ended up being .041 , which is within the gap but a little bigger than i wanted . Compression should be 10.2-10.3 to 1 . They are raised runner and the Edelbrock rpm air gap is port matched . I would run a single plane , but a victor won't work with these heads due to the raised runner ( .210 i think ) plus i would have to have a new intake ported and this is only a "street truck"
I will be topping that off with a cheater plate and 750 speed demon . This will be my 4th speed demon and i have never had a problem . Might step up to a custom built carb later .