I assume it has the TQ 4 bbl carb , anything to help air flow is the key , K&N air cleaner , better cylinder heads would be key , if you can find some 2.o2 valve heads or the later 308 castings it wil cost for head gaskets & intake gaskets only to swap heads , cam choice will make the biggest difference but would cost a few $ for springs cam & gaskets .Other than that simple tuning will get you a long way