engine and trans swap
 

I have a 77 gmc crew cab 2wd with a automatic trans and a 454 in it. Only has about 30 k on both the trans and engine. I also have an 86 chevy crew cab 4x4,4 spd with a 350(was a diesel from the factory). anyways I want to swap the 77 motor and trans into the 86.The 86 already has the auto steering colum. I have heard that I would have to put on a smaller tail shaft on the auto to make it fit to the transfer case. Or should I leave it a 4spd. It seems to me that it would be an easy swap for the most part. What do you think? Thanks