[Keithc8]

Like was mentioned just use the two trottle bodys with the fast system with the right tuning would work great. I believe with the right camshaft and carburetors you could make the 2X4 deal work good. We have done some 450 vacume secondary carbs that have worked great on the 2X4 engines that are very drivable, you give up a little HP but they would work fine on 625HP engine. Good luck, Keith Craft