Unless your running rocker arm girldle there should be no reason to run tall valve covers. Maybe I read your post wrong but I don't have tall covers and they fit fine as for the longer pushrods, either the 23* or the G2 you have to run longer pushrod on one side I forgot which one, call 1-800-630-1555 that is trick flows tech line they will know. I didn't have to run longer ones with mine becuase I have the older style twisted wedge heads. As for the cam question, it depends on alot of different things. What fuel system you running, carb or TPI?