MUFFLERS, what should i get?

Dyno Max Ultra flows .

X2 as far as mufflers go. Turn down ahead of axle would enhance the sound and feel of what you have now. Carbon monoxide warning with this one.

As far as factory exhausts go, I was a big fan of a 65 Formula S Barracuda (non CA) in my neighborhood and the chambered exhausts available on the 67-69 Z-28 (no muffler).