There is a page on pitching in the primer at my WWW site. FYI: I
routinely record 78s at 45 rpm (with an appropriate stylus, of course)
and make the correction when reading the file into the computer. I also
transfer open-reel tape at double speed on occasion.
In each case - including yours - pre-emphasis is different for the two
cases, so expect to have to reequalize. Any audio editor should do the job.