pushrods for magnum head conversion
As far as cams go with using magnum heads and the 1.6 ratio rockers, it looks like the Comp Cams XE268H is about as big a lift cam that you can use without having to have some work done to the heads. That cam is built and rated for use with a 1.5 rocker ratio. The lift numbers of .477 intake and .480 exhaust are effectively changed to .509 intake and .512 exhaust. Anything under .525 should be ok... just be sure that you do the math to make sure!
Also... the longer exhaust duration (280) of that cam is good for scavenging the combustion chambers... more efficient, and potential for better mileage numbers. (if anyone cares about that)