I put a T56 in my old 89 Firebird after taking out a T5... so much happier. It was from a 95 TA / 2.66 1st, .5 6th.
3.70 gears in the car... it's awesome. If anything tho a .62 6th gear would be better. .5 is just too much.

The TKO600 made me so much happier than rowing the 833 in the Charger... the only perceivable problem is the big drop from 4th to 5th with the .64 5th and 3.73 gears. Somewhere between 45 to 50 mph I start thinking about upshifting but I really need to wait till 55ish.

If you got the guts I'd do the T56... I sorta wish I did myself.

If you got a friend with a T56 equipped car I'd recommend taking one for a ride just to try it out.