Hoping someone can give me an answer to a quick question. I just got a 1994, Chevy, K1500, Z71, 4WD pickup from my brother. It has a 350ci, 5.7L, V8 with throttle body injection. I'm thinking of rebuilding the motor. All the books at the bookstore on rebuilding specify small block or large block and I don't know which I have. Also, if you could recommend a good book on the rebuilding process. Any info would be greatly appreciated.  

At the risk of sounding like a butt, I would advise you to have someone else like a shop, do the work for you. All the years that chevy has had a 350CUIN. motor, it has been a small block including the LS1/LS6 series. That is common knowledge by all standards, and not knowing that, brings into wonder if you have enough knowledge of vehicles to do this, assuming you were going to attempt it. Building or rebuilding a motor correctly requires quite a bit of knowledge, skill, and tools.
There are great shops out there that will not empty the bank doing your motor for you.
If that is not an option, find someone who walks a good walk, not talks a good talk, and have him do the work while you assist, or just watch.
Internet, or other research is mandatory to understand the intricasies of a reliable job.
Be careful when choosing your help. I had a $16,000 long block built by someone else, a professional shop highly touted, and have had several problems with it related to their work. To make things worse, it was a shop half way across the country. I wished, at that point, I had done it myself.  
Most times, spending a little at the beginning will save greatly in the end.
Good luck.  

There are several different directions you go. If you want to build up your existing motor, there are certainly plenty of options for the 350. Headers, manifolds, cams, lifters, superchargers, you name it.

The '94 350 was the older style small-block, which was replaced by the Gen-III motor in the '97 Vette, and then in '99 in the trucks. There are a lot of guys that like the Gen-III and Gen-IV motors because they're lightweight, compact, and like to rev, but there is no shortage of parts for the older-style small blocks.

A really good guide is the Dr. Whaba series from Scoggin-Dickey. They're a little on the pricey side, but I've heard good things about them. I'd just Google "Chevy small block rebuild" and you'll probably come across dozens of books about doing rebuilds and engine swaps. That one is for the '96 and newer models, which are port-injected, but if anything it'd be easier on yours, since the '94 has throttle-body injection. Hope this helps!    

Thanks for the feedback onebad. I'm new to automotive engine spec's so I haven't aquired the common knowledge just yet, but I'm a quick and eager learner.
I'm a Biomedical Engineer so I'm hoping I can handle the technical end of things and armed with a GOOD book and the right tools what better way to get familiarized with my new, old truck. And one thing is for sure, I'm not assuming it will be a piece of cake. But it's not my main ride so if it never runs again it wont hurt so bad.
Sorry to hear of your bad experience, but one thing I'll never be able to say is "I wish I'd have done it myself".
Thanks again for the feedback and being there to help. It's very much appreciated.  

Thanks esanchez for the info. I'll check the link you provided. And armed with the info provided by onebad at least now I know what I'm looking for.
Thanks again.
Isn't the internet a wonderful place.  

No problem. We all started somewhere. Guys aren't born knowing what a small-block is. Although in some families, they do by age 5.  

You've got a good platform to work from, as there are plenty of parts out there for those trucks, for rebuilding or customizing. Keep us posted!