Suggestions for muscle car sound muffler without drone

Update:

I replaced the valley cover since I had a small oil leak. I thought the exhaust got louder after replacing the valley cover. I decided to try not cutting out the opening in the metal valley cover for the exhaust crossover for the intake manifold. I'm surprised how much louder the exhaust got. I put a different carb on but it's still a Carter and the same cfm. Only difference is not cutting out the valley cover for the exhaust crossover. I've run the car for years with the heat riser full open without any problems so I thought I'd try leaving the crossover blocked off. It's made a noticeable difference. There's a gasket glued to the valley cover for the intake so I should be able to just unbolt it and dremel out the metal valley cover for the crossover. Note the difference in db level for the drone spike! First photo is with the crossover open and second is with it close.