I just used a regulator calculator like I normally do and it has always worked for me. I am running un-governed I think this motor was rebuilt and there is not governor unit on the carb even though it is a model of carb that would have come with the truck

1967 Chevy c50 327 w/ sm465 5000Ib front 15k 2 speed rear w/ 22k springs, single axle, hydraulic brakes