The older MSD boxes have a plug in chip for the rev limiter. It is typically whet with a number (the rev limit) on it that can be replaced. The newer MSD boxes may have a dial with an adjustable rev limit on it. If you are not seeing any drop in
oil pressure, then probably not a major problem. If you burned a bearing,
oil pressure should suffer and you will start to hear noises that will not sound good. More than likely you have survived a potential major problem.