The only FMX converters I have dealt with are the pretty standard 12 inch units, they measure about 12.5 inches on the outside edge. It wouldn't be too complicated to put one together with the marauder components for stall, but I just don't know of anything "stock". I am curious about that flange myself. SUre would be much cheaper than cobra's and plentiful in the bone yards.
I have an SFI flexplate available that will work, I just ordered one for a guy yesterday.
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