Sorry about the dumbass questions, normally i would just ask in the newbee forum but im lookin for semi-correct answers so...

I found a good deal on a motor/tranny for my truck but its outa a 2WD, so i wondering what would need to be done to the 2WD tranny to bolt up a 203/205.

You're right, stupid ass question. The reason it is is because you didn't tell us what tranny it is. Our answers could be more direct. It is as easy as finding the right tail shaft and factory adaptor plate to make it all work. best bet, junk yard or a friend that has a blown tranny on a tc he doesn't want anymore
To swap the tail shaft, you will at least need to know how to tear a tranny all the way down and put it all the way back together. If it is a 4 speed or other manual, you will need intimate knowledge of what you are doing as well. Come a little more specific and you will get help

what kind of transmission?
Most likely the tail shaft will have to be changed. To get to the tailshaft to change it, the guts have to be taken out of the tranny. Also be sure you have the correct adapter to go between whatever transmission you are using and the transfer case. The engine should need no modifcation.

Blacksheep beat me to it

Sorry about that i was in a hurry when i wrote...

Its a SM465

There are two possibilities of how to bolt a doubler to a 4 speed, and neither of them are popular.

The most common way would be to use a 10 spline output 4 speed and locate a 203 with a 10 spline input. This is rather rare, it was only offered one year IIRC.

The other way would be to use a 32 spline output 465 and I believe the adapter from an 85-91 K30 with a 465/NP 205 combo. This is a hard adapter to find as well.

I'm not 100% sure on the 2nd way of doing things that I mentioned, hopefully someone here can give you more info.

The short answer is that it's relatively difficult to find the correct parts to put a doubler behind a 465.

My suggestion: sell the 2wd Tranny. Buy a 4wd tranny.

when you typed 203/205, we assumed you meant doubler. If you mean you don't care which one you have on the back of it, that is easy. If you mean doubler, I think you are pissing up a rope because of the deep ass first it already has, but whatever. 1974 chevys all came with 203's, even behind the trusty old 4 speed. that is the route you need to go for the doubler. If you just want a 465/205, aka: the strongest tranny/tc for the money in Chevy Land, look anywhere and trip over one for under $250. If this is too cheap, maybe we are just flooded with them here because people can't wait to get rid of them. they seldom blow up. ditch the 2wd tranny or keep it for parts that you will never need and go find a tranny/tcase out of almost any 70's chevy.

better deal for a doubler is a new 32 spline ORD custom mainshaft that mates to a 32 spline 203

for a 205 to bolt up to a 465 it is easier to buy a matched set tranny and transfercase
the are cheap