I contacted a rebuilder that said hes selling a 46re trans thats heavy duty.
The readers' here said to ask him whats makes it heavy duty, and he asked me to call him.

Can I get some Key question to ask, so I can report back, and get your input

 

Torque converter, manufacturer, stall speed.

Sonnax Sure cure kit installed?

New, or reman/refurb solenoids?

Extra clutches/steels? Brand? Composition? (what are they made of?)

Any upgraded "hard" parts?

New bushings?

 

^^^ solid questions.

To add one more: plastic or metal accumulator piston (stock is plastic, upgrade is metal)?