The engine 360 .030 over kb190 pistons,Decked to 9.588 .509 cam/ Ported j heads with 2.02 intake plain old hooker tube headers. If my calculations are correct has a 12.5-1 compression and I'm running 50/50 mix of sunco 110 and pump gas 93. Total timing 34 degrees. Need to get a new set of plugs and wondering about a good choice. Any recomendations?