An update - FINALLY!
We're down to a #51 jet. The mileage has picked up about.3/mile to just under 17 mpg.
I've discovered two things. 1st, the stumble is occurring just before the power valve opens, whether driving or revving from idle (happens between 4" and 6" of vacuum - presently have a 3.5 PV). I will be changing to a 6.5 next depending on what you guys tell me about my second issue. 2nd, the secondaries are opening when revving the engine from idle.? Just as the stumble dissapates they start to open and they will continue opening until I release the throttle. I have the stiffest spring in the Holley 7 spring vacuum secondary spring kit installed.
Why is this happenning? I thought the secondaries would/should not open when revving the engine from idle? Is this a symptom of another issue or just a lack of gas due to the pump shot being too small, too low a PV, too small MJ's or a combination of any of the above.
I had thought the lack of power prior to the PV opening was just that, but maybe the secondaries are opening at approximately the same time as the PV. I will be checking with a paperclip today or tomorrow. When the vac get to 3-4" during acceleration I can feel the power increase.
As always, thanks for any input
