I think with the 413 you're going to be close to 12.50. The 528 is a nice mello cam. Depending on what else you have. I'm guessing you have headers, a decent intake and electronic ignition. If so leave the 413 in. Even with the 509 in the 413 I don't see a problem. If you ran the 509 with ported heads, good headers (1 7/8+) and 4.10's it MIGHT run 12.20.