Yes, there is new hardware available today to the old CB750's
I would like to have 915cc, Mike Rieck ported head with bigger valves, (max for street), matching cam, Mikuni TMR 32's
APE Ultra crank with rods, lightened alternator, and maybe undercutted trans just for sure. I have missed 2:nd and 4:th on my bike some times when shifting gears too sloppy.
I can buy a very good not old 1000-1300cc not that old plastic racer with 150-200 hp for those money... But I do not feel any thrilling feeling in my stomach when watching the newer bikes as I do with an old CB750 or Z1-900/1000 from the 70's...