If you buy a carb with a dual bolt pattern you don't have to redrill the manifold. Some vendors sell dual bolt pattern carbs. Another option is to use a large 4150 flange carb. I use a QF-1050-AN carb on the dyno and it makes pretty good power compared to a 1050 Dominator. Not quite the same power, but usually only gives up 10 hp to the 1050 Dominator.