I am FAR from an FE expert!...but I do recall reading somewhere here on the forum that the 428 crank does use some different parts. It was related to balancing, IIRC...and could well have been related to the flywheel needed to balance a 428 crank?
Could the 428 crank and the corresponding attachments be your issue.....?
Wish my memory were better, but the world of FEs is, for me at least, a sort of mystical, magical place where things don't always make sense.
Cheers, and good luck!
Dugly