Maintenance Manager reported an engine Hydro Mechanical Unit with the wrong effectivity was installed because of part number confusion. The aircraft was taken out of service and the correct unit was installed.

Narrative

The #1 engine was replaced in ZZZ1. Shortly after installation and a successful check flight; there was a torque split in cruise and ITT (Intermediate Turbine Temperature) issues. The ITT issues were fixed and the TQ split was being troubleshot every day. There were no spare aircraft and it was impressed upon the ZZZ1 maintenance crew and myself that this aircraft must be up every night to not miss a run. The original plan was to change the HMU (Hydro Mechanical Unit) but the part was lost in transit from ZZZ to ZZZ1. I was asked by the director of maintenance what can we do to get this aircraft up and ready. My response was to send the spare aircraft (Aircraft Y) from ZZZ to ZZZ1 so Aircraft X could properly be worked in ZZZ1 with more experienced mechanics. That plan was rejected. I looked up a fuel pump on the System portal. There are quite a few listed with different effectiveness (Example: A; B; C; D; AB; ABC; ABCD; etc.) I confirmed and verified a P/N with Maintenance Control and the ZZZ1 mechanics did the same. Ultimately the wrong effectivity was installed. I am the ZZZ/ZZZ1 Hub Manager and was working from ZZZ at the time of this incident.