71 3/4 2 wheel drive to 4x4 conversion
 

Is there anyone here who has already done this that can give me advice about making my 71. 3/4 ton 2 wheel drive into a 4x4 it has rear leafs already basically i just want to know the amount of work involved and parts i will need and what years will work on my truck i would leave it the way it is but 4wheel drive will be a necessity in the future thanks for any help fellas