I have a motor very similar to yours, 518 low deck pump gas(10.29 to 1 comp. ratio), I have ran it with a set of ported Eddy RPM and a set of 440-1. I have another motor, 527 C.I bracket race motor using a 440 block with M.W. size SR heads, they flowed 340 CFM at .700. That motor(12.9 to 1 comp ratio on race gas) made 775 hp with a single 1050 dominator, the 518 C.I. pump gas motor with the 440-1 heads and the same 1050 carb made the same HP on the same dyno late last year on Oregon pump gas The 518 with the CNC ported RPM heads made 718 HP and 744 Ft. lbs on the same brand pump gas as it did with the bigger heads My point is aren't the Victor heads standard 440 intake port size? If so go with the biggests heads you can. BTW don't be suprised if that 511 C.I. motor turns out top be a real tire smoker Mine is