So, my recent build is a 500 stroker RB block. Bought it as a .040 over 12.5:1 domed piston motor. For my build I went with a -6 cc dish piston with the Stage 6 heads that should give around 10.5:1 compression. Motor had a Autolite Racing R3933 plugs in it. I'm running 110 fuel, but went with a step up hotter AR3934 plug. Think this is an ok heat range? Or should have stayed with the colder plug?