buy the 383 for $450. great price. TBI will work, but u need bigger injectors. use holleys stealth ram intake for more torque and horsepower. U will have to wire the computer still if u havent done that. If u go with a carb, use a edelbrock intake with a holley Street Avenger or Edelbrock Thunder Series carb. I used the thunder series on my 305 in a caprice('88) and it ran real good. If your running a 700R4 transmission youll need to get a lock-up kit for it. Youll also need the kickdown bracket either way you go(Carb or fuel injection). If you dont buy this you will burn your transmission up, I burned mine up. Since your workin with $900 I would use a carburetor because injectors arent cheap. You will need...
around $500 for avenger or Thunder series carb
around $150 for distributor(and kit)
around $100 for lock-up kit(Transmission)