I'm trying to document the major tuning differences in the original Holley 780 CFM carbs as used on the '67 thru '69 Z28's. As I understand it:
- List #3910 was used only on the 1967 Z28, while List #4053 was used on both the 1968 and 1969 Z28.
- List #3910 used #71 primary main jets, while List #4053 used #68 primary main jets.
- Both carbs used #76 secondary main jets.
- Both carbs used a 6.5 primary power valve and a 8.5 secondary power valve.
- My original List #4053's metering blocks have 0.063" dia. primary PVCR's and an 0.067" dia. secondary PVCR's.
Has anyone measured the primary and secondary metering block PVCR dia.'s on their original List #3910 carb?
Chuck B.