Thrust Bearing Failure

[Belle66]

On 318 Poly Engines.... and common to most all early hemi 331/354/392 Engines

The #5 Main Main Bearing Vertical Oil Clearance is critical... and directly proportional.....
to:
the amount of Oil 'leakage'(lubrication) out to the Thrust face of the Bearing.

Forget specs
.0025" Vertical Bearing Oil Clrc on #5 is absolutely critical, with less than .0005" taper present in the #5 Main Bore.

Did the engine exhibit absolutely wonderful Oil Pressure at all times ?
If yes ?
then I would suggest some investigation of the #5 Main and Main Bearing Clearances in general may be warranted.

PS
with a 727 Chrysler, I have NOT heard of any Stator/Pump issues that can facilitate Convertor 'pressure' being exerted on a Crankshaft.... other than the as mentioned "clearance' that must be checked/present during installation between the Convertor Lugs and the Flexplate(full pump engagement)

Very interesting, thanks, and yes the engine oil pressure was good. I'll do some checks.