Richard, Here is a substitute clutch plate for the Ford Long V8 plate.
You do not have to enlarge the center arms and theybhave the correct angle for the Ford throw out bearing and hub. There is a 10 and 11”. The 10” is the one.
https://www.rockauto.com/en/catalog/...ure+plate,1988
Ford Barn V8 discussion.
https://fordbarn.com/forum/showthread.php?t=159786
John