The best investment you could make is to buy the painless TBI harness, and the wiring on that is done for you. You can get edelbrock intakes for the TBI, and a chip, and then there's nothing to worry about, the computer takes care of the tuning.
Most of these 4.3's in the Blazers and S-10's get really poor fuel mileage (worse than a same-year 350 in a full-size truck). In the half-tons they can get mid-20's, not sure why that is.
