A little update on this thread..
While looking for a replacement truck, the VFD found out a neighboring town had one in storage that hadn't run for 3 years. Upon inspection they found it was an M54A1! They got the OK from the town and the DNR and secured the truck. I found the IP had a stuck rack and 5 plungers, so I swapped the IP from the bad engine and it runs great! Pretty lucky to find another Mack powered truck so close.
The truck with the bad engine will probably wind up on an auction soon, either on-site or at the DNR yard near Ames.
