I found a set of these fairly cheap, they are fresh from the machine shop, got .600 lift springs. 2.02 intake and 1.90 exhuast valves, think they are worth $600? My motor is a 306 with a E cam, getting ready to put a ported cobra intake with 24lb injectors and maf, and 70mm tb on it. Think the Heads would be to much for my combo?