G'Day Frank, that was rear wheel horsepower mate. Those "busa's must have been stockers though, my old GS1000 based drag bike would pull 9's all day, and when I pulled the engine out and stuck it in a road bike, it'd still do 10's, and was reliable.
Talking about reliable, sticking blowers, turbo's, monster cams and 1000CC plus kits to CB750's will make them as fast (theoritically) as a modern "off the showroom floor" GSXR, CBR etc, and they sure do look cool, but that's where it ends mate, if you want to go really fast, I'm talking "poo your pants fast" then commute to work, go around corners, do some touring, etc etc, buy a modern bike.
My bog-standard BMW K1100LT has about twice the RW BHP of a CB750, handles better and has phenominal Brembo brakes, will do 140 MPH all day while I listen to my favourite Mantovani concerto, and returns a minimum of 50 MPG. It's a typical modern touring bike, boringly reliable, and with just under 100,000 miles on the engine, has never been apart, and probably won't need to be, in my lifetime.
Don't get me wrong, I love cutting up quite country roads on my K1 "Power Kruiser" while listening to the 836cc race engine's mechanical symphony, but nowadays, it's only "fast" when compared to other bikes of the era. My stock Suzuki GS1000S will eat it for breakfast, and it's 27 years old this year, and just about anything over 500cc's built in the last 10 years will crap on it. No biggie, I love it, but I don't bullshiit about it either...............