Old skool here, '72 440 bored and stroked to 499,11.5-1 compression,346 heads,MSD box, blaster 2 coil. Using AC R43 plugs,cheap!! and seems to be the only plug that will last in my combo.The same plugs for 4 years now,lots of passes and street driving. I just wish they still made the non-resistor plugs :-(

john