Mopar Differential gearset.

I have pretty much decided I need to do a gear change in the replacement differential I bought. This differential is a Mopar 8 1/4" from a 1974 Dodge Charger. The ring gear has 46 teeth and the pinion 17 teeth. This equates to a 2.71/1 ratio. I need something in the range of a 3.91/1 or close. With my overdrive transmission at the 3.91/1 ratio I should have a good cruising speed at moderate engine RPM,s. Do any of you old Mopar folks have anything sitting around that might work for me?

Thanks, Don Coatney