Hope to find help

[PK]

If you tell us what codes you are getting, and why you went for an engine rebuild in the first place, we might be able to help more.
Especially how you know "was running rich on the drivers side".

PK

[Y33TREKker]

Double check the cam timing on both sides? these things are somewhat notorious for the timing being difficult to set after the engine has been disassembled to change the timing belt, timing belt pulleys, water pump, etc.