Looking for some basic mods?

I understand where you're coming from, lack luster throttle response. I got the same from my 67 273
Some tweeks that will make it a lot more fun to drive are dang near free. I upgraded the charging system, 2 brl intake and carb, and ignition system, all with OEM parts from a 73 318. I don't have the horses to over power my 10 inch brakes, kill my tired old trans and/or 7.25 rear end but... I can leave the red lights with the rest of the traffic, hit passing gear on a entrance ramp and get out there like the rest. Not to mention how much easier it starts, hot or cold. I haven't touched the exhaust.
I do have a small fortune invested in a complete commando build. A bumper to bumper drive train build that includes dual exhaust, 8.25 rear, etc.., and suspension, and brakes, even wheels and tires.
Honestly, the only part here that I could really enjoy today is the sway bar to stop the body roll. Second to that is the cruise control.
Mine is a Barracuda which is closer to what is considered "muscle car" I guess, if body style makes a difference in some minds. Muscle car is defined, horse power and torque versus weight so any body style can be a muscle car with enough money spent.
You want a muscle car or just more enjoyment from your classic a-body ? That's the question.