I have (had till it was hit) 74 A manual discs/10" drums (same as you/& 7&1/4 I'm assuming) in a 65 dart with the 1&1/8 alum M/C & it brakes flawless tho that is reportedly too large of a bore dia & others have reported way too much leg effort needed with that dia but it has worked for me (& I ain't that strong). Here's a BTT for ya since you ain't getting no love on this request.