making an I6 '69 stang fast.

[TigreTek]

A friend of mine recently bought a '69 stang (coupe) with a rebuilt I6 (#'s don't match). It has a rebuilt automatic transmission. What can we do to make this thing fast, and are there any reliable mustang tuners in south florida. This vehicle is for street use but must be fast. We're willing to mess with everything from nitrous to engine swaps, but would prefer to start out doing things on the cheap. will the old I6 motor take nitrous? or are we asking for catastrophic failure (we're basically thinking of a 50 shot, dry)