I have BBC (427) similar compression, all roller, all MSD, etc... I have ran autolite & NGK while I was re-tuning changing carb & fuel system. Here is what I noticed... the plugs sucked if you are going to be doing alot of tuning!! If they foul, they are as good as garbage. Let's face it, you may foul them getting aqainted with your motor. What i did is bought Bosch Platnum plugs... I have had the motor way rich, when conventioal plugs would have fouled. Not the Bosch... best plug I ever used. I am no expert here, which is why I needed a strong plug that would not foul while I was learning.