74 CB450 Forks

I have a 1974 CB450 that someone back in the 70's put a 10" over fork on. It had a tall sissy bar and a king and queen seat with ape hanger handle bars and twisted chrome highway pegs.

Luckily the seller had the original seat (barely sat on). Since Forks by Frank is out of business, I cannot seem to find a pair of stock length (or 1" shorter) inner fork tubes. They are 35mm, same as a 750 or 550 of similar vintage. Can someone tell me if I can use 550 or 750 fork tubes on my 450? ......or a source for new ones?