727 flex plate?

Thought I spun a rod bearing but it turned out to be a broken flexplate.......what a racket that makes!
So now I'm on a quest to replace the broken unit. I believe this is an internally balanced 318 motor with a 727 with what looks to be about a 9" high stall converter.
I will verify that size when I get it out. Called Mancini to order replacement and he asked what size converter bolts, 5/16 or 7/16. I mic'd one of the bolts and it is 3/8".
They don't stock anything like that for a mopar. Not knowing who made this converter, how and where can I get a replacement?
I would have sworn this was an original Mopar flex plate but apparently not

View attachment 1715993660
thats fixable :)