fuel economy

[Rufton]

You can drive a vacuum secondary 4 bbl carb in 2 bbl mode all the time if you are easy w/ the fun pedal and stay far from red line. I get good mileage w/ 4 bbl V8's when I try.

You can drive carb w/ accelerator pump linkage detached if you don't stomp the pedal. I don't recommend, just happen to know from experience. It does force a good idle tune and minimizes washing precious oil off cyl wall w/ unnecessary cold start pumps.

WOT stomp necessitates healthy accel pump shot and nice fat jets to reduce chance of engine damage.

[IwantaK5]

Originally Posted by jthomass

I believe that the holley double pumper will be dumping fuel with the primaries and secondaries everytime you give it any throttle. Where the vacuum secondary carbs will only dump fuel from the secondaries at wide open throttle.
Seems like switching from a mechanical sec carb to a vacuum sec carb could help quite a bit unless you are at WOT a lot. Just a thought?

Holleys are like a toilet bowl with a garden hose in it.