First plug change.

Well, I'm a firm believer in running the PV closer to cruise vacuum. I average 13-17" vacuum with max up to 20" at cruise depending on speed and the only reason I pulled the 10.5 PV out was it came in a hair too soon when stabbing the gas at 30-ish mph. But, with things down low still a bit outta whack, once I get the transition area dialed it may go back in because I suspect I wasn't completely on the boosters yet. I like to get a leaner PMJ setting and have the PV enrich at the instant I get on the gas from the main-circuit cruise. I realize everyone has different ways of getting the job done though, and I do appreciate your input! Thanks.
I currently have Edlbrock RPM heads, they recommend starting with RC12YC champs. With the same heads and a little less SCR on my 440s I used to run autolite 3924 before switching to the NGK 5, and they worked good.
I love this stuff!


You are probably really close with the 10.5 unless you don’t have T slot restricters. As the throttle blade opens the T slot gets richer, and that’s when the PV starts to open so it looks and IS rich, but not because the PV opened up, but because the T slot is too rich.