what would be a safe plug for a daily driver with a 4 lb lower 2.8 upper and a ported eaton running on crappy 90 octane? i have searched and everyone has a different opinion. all i can get here is 90 octane so that i'm sure has some effect on heat range thanks

 

I think one range cooler like a TR6 would be right.
More importent considering the octane level would be your timing, maybe max 12 degrees, of course a good A/F ratio would be required also. good luck.

 

isn't 12* timing stock? getting a wideband soon so i think that will help, what is the leanest i should run it?