What plugs do you run in your HP 273?

I'm sure i had the 9yc's in originally. My compression ratio is 9.6/1 which is 1/2 way between the original 2 and 4 barrel compression. I think I'll put in a plug that is in the middle of the heat range. I always warm the engine up but I do a lot of stop and go driving with the ol' Dart so a bit hotter plug should work best.