6.1 hemi 6013 msd

Shouldn't be a problem at 13.5v to my knowledge. Most cars are supposed to run over 12v or the battery would never charge. Technically speaking I think the standard output is usually closer to 14.4v. Seeing as MSD is a pretty old company I would certainly hope that they would understand and design around the rather "dirty" power that runs through cars. Been running my MSD box on a old factory electronic regulator with no issues for a few years now.