I have a 91 RS with a 305 5 speed. How do you tell the difference between the TBI and carborated?

 

If you take the thing that looks like a trash can lid off of your intake manifold you could see one of two things:

1) Two big holes with two large injectors over it : You have TBI

2) A Carburator which is kinda like a rectangular type object hehe

If your car has never had the engine changed in it, then it's TBI, RS's came with TBI from the factory

 

If you have a 91 RS and its a 305 ci. You have TBI. RS s were not available with the TPI enignes unless they had the B4C police package. Carbed camaros disapeared from production in 87'.