[sntrym95]

The TBI motor's limitations are the tbi (450 cfm stock), the cam (it's ****), and the heads (also ****). The 450cfm isn't too bad and can handle and upgraded cam to a degree but the computer and manifold vacuum are limiting factors in upgrading the cam much.

the link above for Harris Tuning will give you a wealth of info on the TBI setup and what can be done short of swapping the entire setup.