On gas, go down 2 on the jets and up to 7's on the plugs. I run 8's in my 15.5+ to 1 SB2, my brothers 14+ to 1 SB2 runs 7's. Plugs should maintain the white porcelain even after a few runs, just no specs. A little plug info here.
http://www.dragstuff.com/techarticle...ark-plugs.html