GMDad, According to the "Holley 5200 Carburetor Handbook" by Mike Urich, HP Books, most model are 32/36. The author also states that flow is more important the Than venturi dia.,,, ya so what about throttle bore, anyway. "When first introduce it came in only one size 270 CFM at 3 inches of mercury. In 1978 a 235-CFM model was introduced on Ford and Mercury 4-cylinder engines, with a 23mm primary venturi and 27mm secondary. Since 70 Chevettes have been equiped with a 245-CFM model with primary secondary venturis of 23mm and 29mm." Thanks for model numbers. "5200 introduced on on the 2.0 liter German Ford used in the Pinto, also used on the V6 and 4-cylinder Capri, Mustan II and Cortina. The 5210 was introduced on the L-11 performance version of the 2.3 Liter Vega. In 1977, the 5210 was used on the the new Pontiac 2.5 liter "Iron Duke" and the 2.0 Liter Audi four used in the AMC Grmlin. In 1978, the 5220-same basic family- was introduced on the 1.7 Liter VW/Audi engine in the Dodge Omni and Plymouth Horizon." The handbook is a little sparse on spec.s Hope this helps.
Larry
68 C20 327 daily driver
63 C20 292 Camper truck
65 C10 ? Custom Cab AC,PB,PS,$flasher
