Pontiac Combo's

Rich, the 68 Firebird 400 D port engine is a great combo. You can run well under the index with ( Not Trick ) But good stuff in the engine. The place to spend money right away on it is..... Trans... a 350 or lighter with a 2.75 gearset. 200 is the best choice. A good 8" converter. Fuel system, Not a Holley black pump with 3/8 line. An Aeromotive system, Magnaflow, ect.
A good carb. Start with a good base and work from there. Learn the combo and have fun doing it. Your car is the right car. You have most of the pieces you need. Good Luck....