The TBI is a pretty simple system. It won't take a whole lot to get it running in a vehicle that didn't originally have one. Couple things you would need to look into installing though:
1) A VSS (Vehicle Speed Sensor) Maybe people disclude this imo, essential sensor when they do an install. It costs maybe 60 bucks for an inline VSS, and it only takes a few minutes to install (power, ground, signal to DRAC)
2) A DRAC (No idea what it stands for) This thinger takes the VSS signal and converts it to the signal your TBI ECM needs, you can bypass the DRAC by getting the correct signal VSS right away (but I cannot remember at the moment if a TBI likes a 2 or 4 pulse per turn signal...)
3) An 02 sensor. You'd need to install this into the pipe directly below one of the manifolds. If you have headers, you might need a three wire (heated) 02 sensor that is installed into the collectors. But with the 3/4 length headers a Camaro would have, it may not be a big concern as compared to the long full length truck headers most deal with.
4) Fuel Pump. The TBI likes something like 15 PSI of pressure or so, which most mechanical pumps are not able to provide. You can buy either an inline pump, or a high pressure mechanical pump from Carter, Holley or something. If you go with an inline pump, you'll want to install it as close to the tank as possible, but still below the tank as much as possible to gain the use of siphoning the gas into the pump. Inline fuel pumps usually like to push fuel, not pull it. If you go with a high pressure mechanical pump, your supply line can remain stock, but from the pump forwards, you will need high pressure fuel lines. You'll also need to install a high pressure return line to the tank. Before you use compression fittings for anything, check your local regulations, in some states I hear compression fittings are illegal on fuel systems.
The rest of the sensors should already be on the 89 TBI 350, but make sure they are all there, as the thing that really kills these swap's affordablity is being nickled and dimed on little things.
Of course, there will be a couple of different modules and relays that will need to be installed as well from the donor vehicle, but if you use wiring diagrams from
www.chevythunder.com you'll have no touble figuring all the wiring out.
Overall, its a fairly easy swap. It will be a bit more expensive than a carb if your 89 350 is missing stuff, but they are reliable setups.
Make sure you check out the soldering tips that are given on chevy thunder. I think they are in the Electrical section. Like the 3rd page or something. He shows an extremely good way of soldering wires together. Also, don't forget to get the high quality shrink wrap that has the sealant in it. They are far superior to the regular stuff
The other thing to consider is why you are putting EFI in. If you are primarily going for gas milage, an overdrive transmission will be your best bet to large gains. EFI will typically get similar milage to a carbed engine under ideal conditions. Where the EFI really shines is when it comes to those not so ideal conditions, such as having your rig basically lying on it's side, or up 10 thousand feet from where it is typically driven, or if you live in a climate with extreme temperatures on either end (90 in the summer, -40 in the winter sorta thing)
The last consideration is that of performance. If your buddy is looking for a monster of a car that beats the snot outta everyone with a monster high performance 350, then TBI is not right for you. TBI is senstive to engine changes. They depend on good engine vaccum to run correctly, as that is how they measure how much air is entering the engine. If your buddy is just looking for a maintenance free engine that will have a lot of low end torque, but not so much in the high end (aka, don't expect to rev much past 5000 rpm, if even) then TBI is perfect for him.
Of course, if he is really good with electronics, he can always up the performance with a TBI throttle body from a 454. Its a four barrel monster that provides a LOT of fuel for a small block. You would most definitely need some serious programming changes, but you'd be able to build a pretty healthy small block with it.
