Originally Posted by lewtot184
low rpm 8" of vacuum with an 8.5" power valve? i'd start here.


Thanks for the comments.
The common "wisdom" of PV 2" below idle vacuum is pure baloney, especially with a big cam. Holley just says that for people who don't have a wideband sensor wink Others say half the cruise vacuum which is what I'm closer to. The PV does not flow fuel at idle.

My cruise vacuum is 14" and I also made my PVCRs a normal size (.053 on a .073 main jet). That is another area I'll experiment with someday, maybe try a 9.5 or a 6.5 depending on what it likes. It's neat to be cruising at 14:1 AFR, push the throttle to accelerate and watch the gauge swing down to 12.5 just as intended up

Quote
low rpm is always the fuel waste'er with a bunch of camshaft overlap. loose torque converters waste energy and low gears don't help matters. holley DP'ers aren't known for fuel efficiency either.


I agree... and the DP has two accelerator pumps and they do get used. Out of the box, the DP is known to be way rich since it's intended for strip use WOT, not cruising, and the PVCR is ridiculously oversized.
Like I said, I'm trying to maximize the (relatively) low speed manners. No torque converter here, I am strictly a gear-rower drive