[Tom Goldman]

Drew, I cant say about the SBC manifold, but if it's anything like the BBC version, there is very little beyond the port match and some very minor machining at the carb flange .
The gasket/port match was dead on to my AFR heads ,so that was nice ,but I saw no other benefit other than it saved me the work of matching.
I later did some radius work in the plenum and further matching to the throttle stop base along with completely finishing the runners. this netted about 1/2 MPH .
Overall the base manifold was better than previous non Edlebrock manifolds I ran.