what spline count are your axles now? if you have 35 spline axles now you can use them in your Dana and save from having to buy new axles. after i blew up the 8-3/4 in my 65 Plymouth. I sent a Dana 60 housing to moser here is what it cost me.
$90 dollars to ship with UPS
i think it was $150 to have moser cut down and weld new housing ends on my Dana 60 that i got out of a mid 70 3/4 ton ford
Moser 35 spline spool,4.56 gears ,all the bearings etc to set the rear-end up,billet 1350 yolk,chrome diff cover. This was about 6 years ago, but i had around 800-900 dollars in the Dana 60 not counting the moser 35 spline axles that came out of my broke 8-3/4. so the prices i posted might be higher. like you said i would call doctor Diff, Cass is great to work with and will help you get what you need to make your car safe to race with.
What gear ratio was you ruining? i blew up a set of some what new Richmond 4.10 on my 5th pass of racing my dart fro the first time with its 600 HP 440.I say 600 becasue my 73 dart weighed 3520 with me in it and my best time that day before the rear-end went boom was a 10.66 at 125.00 in the 1/4. also my 8-3/4 has a back-brace. do you have a LBA valve body? if not i would get one. well like you i dint have the money to put the Dana in the dart at the time so i installed a set of used Richmond 4.30 gears and after 25 passes they are still going strong, but my car is not making the power yours is, so my advice probably wont do you any good. Got any pics of the tore up 8-3/4 gears? well hope you get the car fixed and are back out there racing soon.