The best bang for your buck for a stock 1995 5.7L/350 c.i. TBI engine is an Edelbrock Performer TBI 3704 intake manifold plus CompCams 1.6:1 roller rocker arms for higher lift from your valves and less friction because of the roller bearings for the rocker arms.
You could spend more money by installing an aftermarket CompCams hydraulic flat-tappet camshaft, but I don't recommend it.
You could install full/equal-length exhaust headers, a high-flow catalytic converter, a high-flow muffler, and a K&N air filter, but I don't recommend that, either.
The main problem is the heads. The heads are GM "swirl-port" heads. The intake ports have a ramp that was intended to "swirl" air flow to improve low-end torque, but the ramp acts as a blockage to higher air flows.
You could install different heads, but then you'd need a custom PROM chip. I recommend Dave Darge at Powertrain Electronics: