These old engines live pretty happily at higher RPM than some of the newer ones. Try removing the fan and take a drive, and you'll probably discover where a lot of the noise is coming from. Very few people run them above 2500 RPM, and they'll easily turn another thousand without doing any damage. I drove a 1958 Chevy Del Ray coupe with a 235, a 3 speed, and a 3.70 rear end, with 14" tires. It had no problem running 70 MPH, and I could push it to 80 whenever I felt like it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!