[Excaliber]

This of course assumes 85 mph is a reasonable speed for cruising without risk of a speeding ticket. When going with a 5 speed the rear gear ratio, cam profile and 5th gear ratio need to be considered to achieve a reasonable cruise rpm at your expected cruise mph.

High rear gear, like a 3:31 Jaguar? A .6 OD wouldn't be the best choice, .8 would perform better at lower mph.