I have a 1989 5.7L Mercruiser with the Thunderbolt IV Ignition system. Sorry don't have the serial number at work. I want to know if you can swap a V8-22 for a V8-24 ignition module? Couldn't I just retard the timing 2 degrees? I have a spare V8-24 laying around that is good and wanted to know if I should keep it or sell it.