I have a 2009 Chevy Express 3500 with the 6.0. I took it to 2 shops one being a local dealer and both diagnosed it with a flat spot on the cam. Went to dealer bought a cam. Ive watch every video I can and when I opened up my motor nothing under my timing cover looks like anything I can find.

Put it back together and got a code for cam and crank not lined up. Rand like it had a miss. Took it apart again, got number one to tsc lined up the cam gear and now it has a knock (I shut it right off) and runs runs horrible.

I’m looking for help to figure out how to get proper timing on the cam. There isn’t a reference point on the crank gear and there are 2 on the timing gear. Hoping someone on here knows there motors.

Are you sure it was TDC on the compression stroke?

I believe so. It did have air comping out of cylinder 1 on both full turns. To be honest, finding it was a challenge as I only did what I could find on the web to find TDC.

#1 TDC, both rocker arms should have play indicating both valves are closed.

There is a mark on the crank gear (A dot mark by one of the sprocket teeth) and use the timing mark on the cam sprocket that looks like a "threaded pointer" not the hash mark. Align the marks together(crank mark up and cam mark down).

Hope you replaced the lifters also. Scored cam will also have issues with the roller in the lifter. Bad roller will cause premature failure of the new cam. Heads have to come off to replace lifters.