As long as we are throwing options out there... I have a stout TH400 with Coan low 1-2 gear set i might be willing to part with. This trans worked great in my 73 GTO with 3.08 gears. Your engine "thinks" it is seeing a ~3.42 rear in 1st and 2nd gear, but then a nice easy cruising 3.08 when shifting to 3rd.
I slightly modified the 8.5" diff in the 73 with a larger billet bearing cap on the ring side along with an Eaton posi, upgraded 28 spline axles, and a bearing cap support girdle. Had the car running low 11 second ET with a 600hp 461 and zero issues after several hundred drag runs. Note, I did eventually install 3.42 gears in that diff when it was turning its best ET.
As others have said, I would not attempt this with the 8.2 rear. I am not 100% certain on this, but pretty sure you can run c clip axles in most street classes? If yes, i would install Moser axles and new c clips in a chevy 8.5" corporate axle before attempting the same with a bolt in axle 8.2.
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