Well it wasn't the valves/lifters(adjustment), fuel pump or water pump noise. Originally I thought it was a rod bearing, but it wasn't knocking. Well I pulled the head because it finally let go on the lake and had to get towed in. It was the number one piston. I was able to hone the cylinder and put in a good used piston. Runs like a champ. The inline 6 chevy motors are very forgiving. Over the winter new bearings rings, valve job, etc
