Put the Holley carb, edelbrock intake, and headers from the 383 on it. Intall a 2.5" dual exhaust with x-pipe, dual mufflers, and full tailpipes on it (Magnaflow, Pypes, and RamAirRestorations make very good systems). Avoid Flowmaster, many like the sound (although others complain of actually being too loud, and droning at cruise) - their mufflers make lots of noise, but they are still restrictive. There are much better choices than Flowmasters out there.

Tune, tune tune! Buy every book on Holley carburetors that you can find. Understand every circuit of the carburetor and how to calibrate it. Learn the in-and-outs of ignition timing - there's some good info. on here actually if you do a search - then recurve the distributor.

That's about all you should bother with until you can afford a better engine.