what spark plugs

I have tried in the past year on my 30 over 340 with headers, exhaust, camshaft etc... champion RN12C, Autolite equivalent, and NGK equivalent plugs... I am no mopar genius so take this with a grain of salt...

With all the different brands of plugs and in no particular order... My car starts right up, idles, drives fast, drives slow, stops, and turns off...

A couple of times I even mismatched the plugs and had the same results. Good luck with your search.