1976 Trans Swap Q

Hi, am wondering about the feasibility of swapping the Muncie out for one of
the side loaders from an early eighties Chevy truck. I think GM calls it the
NP260 (MY6) which I guess is like the old New Process A833, which is really
a 3 speed with Overdrive. The ratios are :3.090 1.670 1.000 0.730 It's
basically a stock engine, so with 180 HP am not too concerned about tearing
it up. The looks and runs great, but the truth be told, my wife and daughter
are the only ones that drive it. If it got better mileage and it was an
easy swap, I might go visit the wrecker. So if you can clue me in on
splines, yolks, tail shafts and shifter placement,ect, I'd be much obliged,
thx