I believe the CB450 is the most impressive bike ever made until.....the CB750. VERY technologically advanced at the time - DOHC, Torsion Bar valve springs, CV Carbs, electric start, ......
A used 1965 CB450 was my 4th ever Honda, I bought in 1966. It would outrun every stock Triumph 650 and BSA 650 in the neighborhood. They had to bore them to 750cc to keep up with my 450.
1965 CB450-1000196, with 4,613 original miles on it, is in my warehouse needing a little TLC. Other priorities right now.