With a 6000 chip in the MSD It hits the rev limiter at around 5700. 300 rpms off on a tach I can barely see who cares about the accuracy. It looks better then a blank or a factory tack that the needle doesn't move at all. And who sees it but me? If you are using it for accuracy buy one like this with a recall. They also have the decal for 67-69 we used in a Barracuda pictured.