is it a after market cylinder or is it it the stock jugs with big bore sleeves?
you can run them with a 4 mil long rod crank but you'll possibly need domes cut and the port timings corrected. You can use stock carbs.. but it'll be holding back the motor. As far as the head goes.. I'm not 100% sure but I think I heard someone say 69mm is the biggest the pro-design style domes could go.. I know the trinity style domes can go bigger.