Have used autolte plugs only real issue for me was reading them. For me lot harder to get good reading on them. Others may have different results.

quote:

Originally posted by markemark:
Has anyone here used the Autolite AR 3933 Racing Spark plug vs the NGK R5671A-9 #5238? Opinions?

I just put a set of the ar3933's in my engine .
It ain't a racing deal , they're in my pro street car and just do cruising (with a Lil rip here and there) lol