If there was a way to transfer the Sytem 7 sounds to a recent Mac it would be convenient to open them with iTunes (which will play back System 7 sounds). On opening the files in iTunes a file name extension ".sfil" will be added. iTunes allows to export the sounds to AAC (which creates a MPEG4 file with the extension ".m4a"). Because of the original data file contains a resource fork iTunes on a Windows PC most likely will not handle the files correctly.