My engine builder recommended a gap of .040 and the Champion RC9YC5 plugs, which is what I use with my full MSD setup and my Edelbrock heads. Edelbrock recommended one notch warmer, the RC12YC5 plugs in fact. MSD recommends that you go colder than what the head manufacturers recommend, so I guess they would want to see the RC9YC5 plugs. They also recommend a little bit wider gap than .040 with a 10.6 to 1 compression ratio, like I have. I've always had good luck with Champions, but WTF, there's no shortage of guys that say they're crap either.
