If one bank of cyl's is running with the RV cam, it's highly unlikely for the cam to be the cause of the other bank's suspected inoperability.

Have you checked compression on all cylinders?

If the valve lash is set too tight, these motors will not run. Low compression readings in several cylinders would make me suspect lash problems rather than mechanical failures in a new motor. You could always try backing off the preload 1/2-3/4 turn on each rocker arm locknut on the pssgr's side valves and see what happens.

Also, have you checked & double-checked the firing order?

It's 1-2-3-4-5-6 clockwise around the cap, with 1-3-5 on the pssgr side and 2-4-6 on the driver's side, 1 and 2 being at the front. Another thing that's very easy to get swapped and real hard to tell what's wrong.

HTH & let us know what you find.