[edwhite7]

Sizzler is correct as to the carb size. A dual plane will need more carb than a single plane. If you take a close look at the runners on a dual plane you can see that only a portion of each carb is available to each cylinder. I had a dual plane with two 650 vac secondries and a single plane with two 450 mech's and I like the 450's best. I tried both progressive and non linkage and the non progressive setup is much more responsive on my car. Watch the power valves, the 450's come with 85's and the 650's come with 65's. With any cam the 85 power valves will probably be open at idle.