Pretty awsome undertaking! Great skills and a shop for the task! Very nice!
I haven't read the whole thread yet, but saw the mention of transfering power to the rear, not sure where your bearings fit in, but...
Years ago, I believe it was Fitapaldi racing in the Mexico GP he rean a VW (may have won, don't remember) but they mated up two VW engines using a doughnut, two very rubber small rings that were looped together and bolt to a plate for each engine. It took the jerky-ness out of two independent engines.....
probably use something similar for dragsters, and, in all these posts it's probably been mentioned that Land Rover has a snow utility vehicle using a power take-off I believe.
Looks like you have it well in hand, just thought I'd mention something but you probably are already aware of such stuff.
More pics.....