jeep grand cherokee 5.2 as donator for my dart gt -65, what gearbox should i use?

Hi! And thanks for a great forum!
I plan to take apart my jeep grand cherokee 5.2 automatic and take the engine, radiator, maybe the power steering box, and rear axel if it's stronger and for the LSD and mount it in my dart.
But what gearbox should I use? Can I use the original from my dart, or maybe the jeep gearbox fits in the tunnel and can it be used without the transfer case? Or suggestions for some other gearbox?

I know it's more electricity job with the jeep gearbox, but with more gears and that I know it is in good condition are big advantages. And that's is free of course, hehe. All suggestions are welcome!

Excuse me if the language is bad, I am from sweden, and writing from my phone right now and trust the correct spelling feature :)