Don't know about the 63, but the HEI did fit the 232,199, and 258 engines IF, and I said IF, if the drive gear was changed. There were some guys on ebay that sold the drive gear for the HEI so that it could be used in the 232-258. But, have you tried the distributor from a 78 up 232-258? That way you could used the Motorcraft electronic ignition system.