Basically a complete drivetrain upgrade.
The engine only makes around 105hp but has something like 265lft-lbs. You can use a 4-speed GM transmission to it. Probably a 4L80e. Although a TH400 would also work. NV4500 will also work.
Then you'll need to upgrade the rear axle for sure. You will also want to upgrade the transfer case. A minimum would be a HD output shaft. A better option would be to use a 241, 205 or a Atlas/Stak. You'd also want to upgrade the front axle while you're at it. You could get away with the D30 but it would be your weakest point.
Oh and like I said, the engine is tall. You'll need a body lift and still might have to cut a hole in the hood.