I had a similar setup with my old 455.
It had '72 7F6 heads, HO intake, Q-jet.
The cam was a custom grind Comp with 237 deg @ .050 and .488" lift, 111 LSA.
Basically, the only trick piece in the motor.
With stock hyd. lifters, it was a bit "choppy" at 850 idle and pulled 11" of vacuum.
1973 SD455 T/A
1979 S.E. T/A
http://community.webshots.com/album/16587603rOyvmFCiHs