I don't think I've ever seen a 2.8 engine mated up to a 700R4. You're right about the 4.3L V6 bellhousing bolt pattern- - - -it matches late sixes and all the V8's I can remember.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!