[Cracker]

Without going into detail - which of the main bearings were failing? The reason I ask both of the questions is windsor motors are prone to failing the first main bearing (by balancer) if you over-tighten the alternator. I had it happen to my windsor and it was diagnosed remotely by Eric and Peformance Engineering in OH.

If you over-tightened your belts after that March pulley set it might be related - unlikely but possible. Just food for though for the future. Best wishes.