I've done quite a few engine swaps mostly LS based but I will tell you this when I went from a standard aod transmission to a more modern 6 l e 90 it cost me more to do that swap than to do the entire engine. You need to think of things like torque converter a stand-alone computer room under that car. Like the guy said before with enough money you can do it but I truly don't think you know what you might be getting yourself into. You should price out a torque converter you might be a little shocked also you have to think of things like with that 8-speed it's like a double overdrive transmission so when you're in 8th gear the car is going to be completely balless you'll have to do something about the gears in that rear end
I have looked at this several times and the problem you will run into is the the depth of the transmission oil pan.
If you take the center of the crankshaft and measure to the bottom of the engine oil pan then measure the center of the transmission to the bottom of the transmission oil pan.
You will find the transmission oil pan is about 3" lower or more.
The Viper doesn't have the room.
The rear mount Trans like the Vette is the best option but that's a whole new level of fabrication
It can be done but not easily.