I trying to find out what other people are using because my engine is not stock:
84 360 block
speed-pro pistons 9.5cr
comp 280H cam
73 547 heads non smog
air-gap w/750 3310 carb.
Now I wish you said that n the first place! LOL ha ha ha ha.......
Run the RN12YC.
One thing I noticed is some prefur a plug over another one for what ever reason, but what ever runs best in your ride will be best in your ride. Not all engines like the same plug manufacturer, er ur ,,,,,,,,,,
Ahhh ummmmm .....:sign10:
:angry7:
I like the Champs and that's what I find works best. After them, the GM plug works fine as well.