340 Chugging instead of Reving

Rat Bastid said
Ok, if you are 100% sure you are on overlap you need to stop what you are doing and degree the cam. The cam is installed severely retarded. Probably more than 10 degrees retarded. You’ll be lucky if you didn’t bend some exhaust valves being that far retarded.

Again, if you are sure that’s overlap your cam is WAY OFF. That needs to be corrected first before you change anything else.

I'm positive it's at 180. Prior to this process, I used a piston stop and rechecked the TDC mark. The timing tape has the 180 mark BDC. I continued to rotate the crank and found both valves open at 360* from TDC compression stroke.