We ran a air volume sensor to determine volumetric effeicncy on the 572 C.I. motor Rodney is testing on the dyno now, it has a custom built 1150 Dominator on it and the sensor says the motor is using around 1030 to 1040 CFM at and above 5000 RPM to 7000 RPM I used a Holley 9375 HP(nothing bigger) on a motor very much likes yours with ported 346 heads and it ran faster with every bigger carb. I tried on it A good 1050 will work very well, IMO