A warmed over and beefed 700 will handle the 6.2 fine.
The 6.5 turbo will tax it to the limit unless you spend serious $$$$$

The Cummins would have it for lunch

If you decide on a Cummins, use the Mopar 4 speed auto that has the full hydraulic controls.

A local fellow has a 4BT in a 95 Burb with the Mopar box behind it and it is sweet.

If you use the 6 cyl, then even the mopar box needs some goodies to make it better.

Have fun.

Missy