I have some knowledge of Chrysler theory for the swirl port head design. Cam height reflects what Chrysler envisioned for the flow of these heads. Looking at the specs for 360-4 stock eliminator cars there 2 cam specs denoted as SC (small cam .423*/423*) and BC(.462/.473). Any duration is acceptable. Using the same head w/ or w/o "stock head being stock" the small cam performs better. What's going on here?