I'd redo the bottom part of exhaust with SS oval tubing and a Supertrapp or a nascar style muffler and try to fancy it up vs trying to hide it with a panel attached to the rocker.
Another option would be to have the exhaust you already have Ceramic Coated.
A buddy just did that on the fenderwell headers on his big block Dart.
They looks awesome, and they were used crusty headers..
I've been thinking about having it done on the exhaust on our 69 Dart with fenderwell headers, the portion under the car looks really similar to what yours looks like other than flowmaster type mufflers.
This is the place that did his, I'm planning on seeing what it would cost.
Obviously not close to you, but it would be an idea of cost.
https://www.jcmmachineandcoatings.com/
