This engine came with the C5TGF plug which is a very hot plug, I've got some OS R7s which is a medium plug. I was thinking that I could try the medium plug and run 20% top fuel and see what kind of results I can get out of this for the break in period, (my tinking is) Cooler running temps. with the .30 head shim. This will,... chance the timming up some, but I don't think that theses chances aren't that significant to hurt anything.
If the fuel mileage isn't going to make the 5 mins I'll try the hotter plug with the 16% nitro and see what those results give me.