hcar, the stack injection looks really nice but does have some problems with initial setup and holding adjustment for the long term. I have $5200 in ours so far so it isnt a cheap solution.

Throttle body injection (TBI) is a poor man's fuel injection. The GM version runs 14 or so psi and squirts into the throttle body so there arent 8 injectors. The TBI is kinda half way between a carb and fuel injection. Positives: cheap, simple, can cobble one up using stock parts. Cons: not as fuel efficient as real injection, uglier than a pig, not very tuneable

Fuel Injection runs >40 psi and can be either a factory job or an aftermarket unit. The common factory jobs for the SBC are the tuned port and the ramjet. The tuned ports are cheap now, a lot of people hack the code so the controller is easy. Parts (sensors) are at the Chev dealer. The ramjet uses a Mercury Marine controller (MEFI4) and is similar looking to the old Rochester units from the 50's and 60's. Arizona Speed and Marine sells a unit similar to the GM unit. Both work really well at lower revs (5500 and under).

After market units seem to be everywhere now. If you go this route, make sure that the unit has oxygen feedback (O2 sensor). Most of the units that feature "no computer" adjustablility are pretty limited in their abilities and are pretty crude controllers. A good controller vendor will recommend your cam basics, ask a bunch of questions about your motor, and will program the controller for your application.

Expect to spend at least $2K for a respectable setup or up to $6K for something like the Roush stack injection.

Injection is really nice for street vehicles.
mike in tucson