Dont know but definitely had more misfires on the race 7's than the projected tip 5's. Could be that running on the edge of rich may not clean off the 7 like it does the 5's. Gonna leave the 7's awhile and see how they work out.
No experience ever running hotter than maybe a 6 in ngk and that's too hot for most of what I mess with but you are close to 11.1 iirc so not exactly low comp. and if in fact it liked the 5's I'd look real close at the porcelain w/a mag. glass and see how they look but still say #7 if the tunes close...............
Just re read that you ran non projected tips in a 7..........Is that correct cos that's not the best plug for you imo, get the 7 projected tip and let tune this thing............
