I read somewhere along the line that songs on the radio (50's and 60's) had to run about 2:30 or so in order to cram as much play time and still have plenty of room for commercials. If my feeble memory serves well, it was common practice for the record companies in those days to speed up the recording a little to keep the songs down to that time span and of course the pitch went up a little too.

Tweed