NP231CHD = Overkill, but fits. (Beefiest NP231 made)
NP241C = Enormous, and Overkill. Very large output splines..not very compatable with Mitsu stuff.
D300 = Heavy, Unecessary, expensive, and no gains.



= OBD2 computer to control the transmission and engine which adds quite a bit of expense, OR stand alone ecu to control the trans which adds the same expense.

I recomend sell your 4l60E rebuild kit unless you are going to look for a 96 and up Vortec 5.7, and are going to run a stock ECU, and wiring(which I also recomend) 96 and Up ECU's have to be sent off to be flashed to remove the VATS stuff, so they will run at all.

You've got alot to research, and alot of work ahead of you.

I Personally would not spend my time swapping in a 4.3 v8 when I could have swapped in a 5.7 for the same ammount of work.

That Baby LT1 is not going to like your Hotcam.