I dont see just a cam change picking up 8 tenths. But that said your combo is very close to mine. I have a .030 over 440 with 10.0 comp using 906 heads I ported. I also use the Holley Street Dominator with an 850 DP. I use the MP .557 solid cam with Isky ductile iron rockers. And I run 4.30's with a 30" tire. My converter flashes about 4200 at the track and seems to work good with a best 60 ever of 1.58 and a best et of 11.52 @ 116. A nice solid cam will help alot but I think you will need more changes then just a cam to go from 12.30's to 11.50's. Good luck , Ron