Should I keep the "anti dive" forks or should I ditch them.....?
First of all, beautiful work mate, and for once I agree with Lucky, the great work you've done on the swingarm won't hurt anything. I have to say though, I hate those 1980's Kawasaki forks and silly wheels, I guess you used them because they were cheap, but they (in my opinion only) detract from the other great work you're putting in to it.
I think later model conventional forks and readily available modern 17" wheels (or better still, 18" which are a better "fit" on a CB750) would have really set it off, and I think you'll be disappointed with the result if you don't change them, but I really don't mean any offence mate, and I love what you're doing, the engineering side of your build is fantastic! Cheers, Terry.