Ok, I was junking today, looking for parts for later on when I get my knowledge correct, I can then institute that knowledge and use it immediately. I was looking for a throttle body for my truck, and I think I found one. I did my homework, went out in the garage, dumped my little toolbox out on the floor, and started to size up what I needed to pull a throttle body. Tools in hand only what was needed, so that I don't go nuts, bringing home axles, blocks, etc, etc. I walked around for about 20 minutes looking at this and that and finally found a good donor off of a 89 gmc converson van. I liked this because even though the motor was uncovered, it wasn't immediately outside in the elements. Got a tbi unit, two injectors, a large air cleaner, and a small air cleaner - $40.00

It looks just like what I have on mine, bolt locations and sizes match. Is this the only throttle body GM or chevy used for all tbi unit? If not what are some of the others? What's the difference between the 350 tbi unit and the 454 tbi units? Size only?