That ratio is available for the Dana. If you are going to be changing gears very often then you should buy a Strange S60 since they are much easier to work on. The cheapest option is to find a used Dana 60 in a wrecking yard and have a local shop cut it down and put gears and a spool in it. If it was me I'd put the Ford Torino ends on it with the Set 20 bearings so you can get rid of the Mopar adjuster. The Torino ends will give you a ton of brake options. Since it is a ladder bar car you don't need the pinion snubber mount so no need to pay extra for that. If you don't have a local truck shop or chassis builder who you trust then you might need to order it from someone.