I can give you some real fwhp numbers on a stock 1968 440-6pk motor I ran with stock 906's but with a Dominator flange team G intake, a spacer and a sorted 850DP in my old '69 Cuda race car which weighed in@3289lbs at the line, I guess a sorted 6pk set up could be worth some mph over the 850 carb. CR was around 9.5:1 with 0.39 fel pro's, the only race part in the motor was the 290@.0.50 duration SFT cam, that car ran a best of 11,2@119 with that combo which wallace shows to be 460fwhp, later I changed nothing else but went to a ported set of 906's with 2.14/1.81's and picked up to 125mph = 525hp...no dyno's here.