Here's the deal..I own and drive a 1987 GMC Jimmy 4x4(Full size) 350 5.7ltr V8, 1/2 ton. I received a phone call from my best friend with this offer...I help him remove a GM 350 5.7 Crate motor with 24K miles on it from a 1981 Chevy 3/4 ton 4x4 pick-up truck. His favor in return is that I get to keep anything I want from this truck before he sends it to the scrap yard.(Body is shot ! No title). Is it worth the time and effort to install these axles and tranfer case to my 87 Jimmy ? What kind of gas MPG will I sacrifice or gain ? What are the advantages of running these parts on my truck ? I will install these parts myself if I see that its worth the time and labor. I aim to have a rock solid, bullet proof truck..Is this the direction I want to go in ? Any info and advice will be noted and much appreciated. Thanks fellas and ladies /forums/images/graemlins/usaflag.gif /forums/images/graemlins/k5.gif PS..I forgot to ask what series of Danas is the 81 3/4 ton running from factory ? Sorry for the repost.