Help me decide which carb for my set-up. I have a 1967 el camino with a th350, 4.10 gears, 3000 stall, 350sbc. It has about 9.2 compression, RHS 64cc vortec heads, LT headers, msd pro billet HEI dist and a comp magnum 286h flat tappet cam. I have been having problems with my Holley street avenger 670 vac sec carb. I would like some suggestions on which Edelbrock carb to buy. The carb will need vac secondaries and electric choke. The performer series 600 or 750cfm or the Thunder series 650cfm? This is a street cruising car only, no track time.