Cheap 318 performance mods.
Swap meet "Performer" intake- $100-$150
Swap meet 500-625 AFB carb- $100-$150
Local shop dual exhaust- $ depends on shop
Stock Mopar electronic ignition if it doesn't already have it- about $150
Clutch fan if it doesn't have it- $varies but should be about $50
Good quality spark plugs and wires- $varies
Advance spring replacement/tuning- $ought to be real cheap
After that it gets pricey.