You could try a Holley Pro-Jection TBI setup, a 670CFM 2bbl or 700CFM
4BBL is my recommendation since you want low and mid range power. A set of
full length headers and a 3-4 inch diameter single exhaust. Single instead
of dual for the much better low and mid range. An 'RV' cam would do wonders
too, but keep it mild because it is still a stock engine. I don't recall the
name of the company, but they make a distributor to fit almost every
American made engine with a GM HEI setup. Its a drop in and go system, fully
self contained, just add 12V, 8mm(min) wires, the correct spark plugs, time
and GO!

   You can get everything through JEGS except the exhaust which you would
have to get custom bent. It will be hard to get it made without a cat, but
ask some local Hot Rodders and they might be able to hook you up.