Like new, never ran Thunderheader. I do not have a model number and I don't know exact bike/years it fits.
I believe it is from an EVO or twin cam carbed softail due to rear mount and no 02 bungs.
Bought used but going a different direction with my bike. Appears to have only been mocked up.
Minimal nicks and scratches from sitting in shop. Comes with heat shields and clamps. No flanges. Has an '86-'17 Softail support bracket.