I just purchased my truck this summer so I am new to GMC's TBI, 4WD, etc. (had a 280ZX Turbo prior). For those who are in the same boat I am in, there is a web site for purchasing performance parts (truckperformance.com) which will show you what options you have in regard to those performance parts with easy to read and informative info. Not implying that this site doesn't, on the contrary it does. However, you can look up a general part, supercharger, for example, and then it will show you the makes/models/years/etc. that can take this part. I've noticed a lot of performance parts being posted for trucks of different years and different size engines, etc., and didn't know if that would work for my truck's year, engine size, etc. I am sure that site is not an exhaustive list but it will get you on the right track. Of course, it is reassuring to hear from those on this site about their experience with certain performance parts, alternative methods or parts to certain parts, etc., so you do not waste time & money. I wouldn't necessarily purchase everything from that web site because I noticed some things were more expensive than J.C. Whitney and Jegs.
Hope this helps anyone who uses it, as it has me. I am sure I will be asking more questions here once I determine what I am going to buy. Thanks for all the help so far.
'87 Jimmy 4X4 2.8L