Depending on the rest of the combo, using the 6bbl will lose you between 20-40+hp. A 416 I built had a small solid roller, Stage III ported RPMS, pump gas, street car, etc. Went 480 plus with the 6bbl, 530 with an RPM Air Gap and HP950 on the dyno. They look cool on a small block, but they really are not that good. Using a 440 set of carbs mean your jetting and air bleeds will be off. Otherwise they are the identical carbs. Also - the W2s won;t allow the 6bbl to bolt on.
