gas mileage Mechanical vs Vacuum Secondaries

The PVCRs on a double pumper are sized for performance/race apps rather than street stuff, so mileage will be worse with a double pumper even with moderate driving.

This (and the solutions to it) are covered in the "Super tuning and modifying holley carburetors" book.

Supposedly the 750 Double Pumper Street HP carburetors have a "street calibration" so mileage should be better with it than a regular double pumper.


Steve