Ok, here's the whole embarrassing story: I was test running the 16 HP Briggs (repowered) I overhauled in my 3414S yesterday when I noticed a slight vibration. Before I could shut down it turned into a BIG vibration followed by a BIG bang. The drive shaft bolts torn out of the motor fan. It looks like the PO had made up PN 8161056 out of iron pipe. The Parts list calls them "Bearing, Pivot Block", but they're more like bushings I think. Anyway, the homemade ones have an excessive inner diameter and got off center causing the vibration and resultant damage. So I am looking for two bearings/bushings, and also a fan, Briggs PN 691151 for a 326400 engine.