If your going to use a automatic tranny with a stock type or race converter I wouldn't worry too much about it being dead nuts on input shaft to crankshaft center line due to all the built clearances in the front pump and flexplace centering the converter to the crankshaft center.
If the converter will slide into the back of the crankshaft easily installed in the tranny with the tranny hooked up to the motor and the converter bolts install easily, I would use it the way it is :: up:
The ZF 8HP70 has a long input shaft (all the way to the rear drum) and zero wiggle. The adapter plate is a stiff 1/8" steel as well so less flex. JVX says .005 is OK, more requires the .007 offset pins.
I would guess that the A727 has more "flexibility".
We did have a 73 Jeepster Commando that cracked 2 flex plates because the OEM adapter (AMC 304 to TH400) was not true.
