GREAT ! - LOOK BEFORE YOU LEAP ! - Two GM books that are used side-by-side one another are good. They are published by GM, accept no substitutes ! They are; GM Service Manual for your model year; GM Overhaul Manual for your model year; Here is one for $4.99 ==> http://www.ebay.com/itm/1966-CHEVROLET-TRUCK-SHOP-MANUAL-SUPPLEMENT-ST-35-/180821174786?pt=Motors_Manuals_Literature&vxp=mtr&hash=item2a19c82a02#ht_450wt_90 They can be found used, like on eBay amazon, or alibris.com, I bought the 1999 Truck Overhaul Manual for $10 plus shipping, you can also buy new reproductions, but if you are going to use them, they will probably get soiled, so why pay for new ? They are used TOGETHER, because for some reason, at times, the one manual will refer you to the other manual, and if you don't have both, you'll be at a disadvantage. Hope this helps !

You should check out a book called The Standard Catalog of Trucks. Not sure if they have one for just Chevrolet but I know that the main truck book has alot of information about Chevrolet Trucks. As far as interchangeable parts, that a bit trickier!! Lots of research!