Also, if you plan on using 1.6 rockers with 3/8" diameter pushrods (like I did) plan on doing some hogging-out of the adjacent intake runners to clear them. I have these stealths on my 446, .509 cammed, 10.8:1 CR (shaved .065" and using Cometic .027" x 4.6" diameter gaskets) and all the stock internals in my A-12 Super Bee and I am pushing a solid 500+ with my combo.

These heads were a good deal!