Kinda confused on this one. this happened twice back to back. #3 piston smoked the first time. Upon rebuild I used new pistons, cylinders, head with fresh valve job. timing on this motor is set at 4 degrees total when using both systems. pulled another 3 degrees out of this hole. Changed injector also..... system a/f was 12.8/1. I don't have all the cam #'s in front of me but the lobe centers ended up in the range of 114 intake 120 exhaust. Other 3 cylinders are fine just issue with this hole for some reason.......