I have a 1994 K1500 shortbed with a manual tranny in it.  I am planning on putting a 4" lift on it and some 33" tires.  I will also be pulling a small camper behind it and was wondering what it would take to put a 3/4 ton tranny and rearend in it. If I used a donor K2500 from the same era is it a fairly straight forward?  thanks  

As long as the rear end is from a 3/4 ton truck it's a bolt in. Doesn't matter if its a 14 bolt full float or semi-float.  

Only real problem you will run into is the bolt pattern. The 14b will be 8-lug while your front will be 6-lug. That is unless you find the rare phantom 6-lug 14b... I've seen one.. ever.  

I have a 14 bolt 6 lug sitting around waiting for me to blow up my 12 bolt posi  

Lucky! lol

Ok, so now I know of three... (I misspoke earlier)

I had a wheeling buddy with one in his truck, I've seen one at a JY, and now this one.  

Another option for the 14 bolt semi-floater is to change out the axle shafts to 6 lug.  But for only 33" tires I would not be worry about the 10 bolt unless it is to be wheeled hard with a locker.