Originally Posted by Tod74
Originally Posted by OneBadGMC
Sounds lean at part throttle to me.
If you have a power valve, throw it in the trash and put the blocks in place. Jet up 3 sizes and be done with it.
Always thought/was told it was 8 to 10 jet sizes up if you plug power valve. Has worked well for me at 10 sizes up.(secondary pv)
power valves are tricky i spoke with pat at pro systems last week and he told me that if changing from a high flow pv to a plug then 10 jet sizes up. if your using a standard pv non high flow then only 6-8 jet sizes and as far as trying to figure out what pv to run in relation to engine vaccum the he also said 2-3 number smaller on the pv then to your vaccum reading at idle hope this all helps.