The 500 came in mid sized trucks that were advertised as capable of towing 4,500 lbs or more.
I checked into this long before I put one in my Dart.
That towing capacity coupled with the A body being a lot lighter than the truck it came out of gave me the confidence that it would hold up ok.
I pulled mine from a late 90’s Dakota that had a 5.2,
Checked the pan before I pulled it to find it very clean inside with remnants of bright red fluid.
I put a stage 2 transgo kit in it with the updated manual valve along with the “First gear at any speed” option.
New front and rear seals went in as well as a new rubber over steel pan gasket.
No other upgrades, and it’s been flawless for 5-6 years so far.
And it hasn’t been babied.
I don’t thrash on overdrive or lockup.
I paid $125.00 for the trans, converter, dip stick and 7290 yoke out of the local pick a part.
( I think more people should say what things cost, so others could have some idea of what’s possible.)