Ltz 400 skipping time constantly

stock cams?
Flywheel issue....shear key? Would that cause this to happen?

Did this issue happen after the new parts were installed or was the installation of new parts in response to the problem?

by skipping time, do you mean its running rough misfiring, or do you mean you take it apart and find the chain is one tooth off?

Are you taking it through top dead center twice, and cams not in the 10 and 2 o clock position?

ditto, recommend checking against the stickied photos. T on the flywheel marks top dead center. Check the numbers on the cams at TDC of the compression stroke. I always thought the numbering and marks on the cams were a little odd and not intuitive, its good to double check. I hold the flywheel with a socket/breaker bar resting on something when its lined up o it doesn't move.