First off i'm a first timer. That being said i decided to go performer RPM for my 350. I'm using a dual plain air gap Vortec intake with 200cc E-Tec heads. They have a 2.02/1.6. The cam is .488/.510 with 234/244 at .05. I would like to know what size carb to use. I want a speed demon and the price is the same between the 650, 750, and 850. I hear mixed answers when it comes to what size i should use. They all cost the same so it don't matter there. I'm sure i will have more questions down the road. Thanks for any reply.