Some General questions.

Mike P 52 said
My questions are; what are you guys using for torsion bars......the Hemi/46 RH combination will likely he a bit heavier than a 440/727 combo but close enough to work.

Viewing a thread - 354 weight
looks like it is 50lbs heavier than 440

Mike P 52 said
What 8 3/4" rears fit.

all A-Body 66 to 76 8 3/4 fit 66 to 76 A bodies as bolt in (watch bolt pattern A body typically have 5x4" pattern (except Later models 73 or 74???? and newer????, basically when they went to 8 1/4 rear and it went to 5x4.5")

Mike P 52 said
I realize this last question is a long-shot, but does anyone have experience putting a 46 RH into an A body (yeah I know they are SB bolt pattern). What transmission tunnel interference issues did you run into?

Many have done this trans swap, IIRC the trans support / torsion bar cross member has to be cut and reinforced at the top of the tunnel. Maybe some sheet metal beating too.

Other than the cool and odd factor....

WHY?

And Welcome to FABO