Call Rich at 309-287-0354 he has a bunch of 59 -64 Oldsmobile -Pontiac 3 rd members ,and a comlete rear end drum to drum out of his 55,these rear ends are very period correct for your Nomad,I have one in mine and run the stuffing out of it with no problems. (468 4 speed) Most are 35 spline and are almost bullet proof !!!

Depends whether you're talking gear ratios or rear axle widths ("what would work..."/. If you're talking gear ratios, it depends whether you want performance off from a stop light, or good mpg highway, for example. If you want good performance from a stop light, then you will probably sacrifice fuel economy on the highway. So, your question is yet too general to answer this. If you're speaking perfromance "what will work", also coming into the picture is the stall speed of the torque converter, which means the point at which the torque converter stops spinning faster than the crankshaft and fully couples itself to turn exactly in time with crankshaft revolutions. If the torque converter spins faster than the crank to allow the engine to get to a good RPM torque range (for your specific engine configuration, compression, timing, etc), then you will NOT experience a flat throttle response from a stop light, for example. As for rear axle widths, here is a reference that might help you ==> http://www.quickperformance.com/Technical%20Info/sus_measure.htm . For me, I decided to FIRST find a rear axle width that would fit. I found a 10 bolt rear axle from a 1980's gm truck, four inches shorter, but with 2" spacers on each side it should work for me when I get to that point. If you are not in a hurry, look online (eBay.com, oldride.com, etc.) for one that would be a LOCAL pickup, this decreases the number of interested people, very few people pay to have a used rear axle shipped cross-country. I bought mine for $75, complete, from brake shoes to brake shoes, renting a $17 u-haul trailer to pick it up. Find a rear axle that'll work width-wise, look into it's gearing configuration, decide if it has the gears that'll meet your needs. A good book, High-Performance Differentials, Axels, & Drivelines by Joseph Palazzolo here ==> http://www.alibris.com/booksearch?qwork=11823513&matches=15&keyword=automobile+differentials&cm_sp=works*listing*title se

Sources: I've used the book and the weblink; I've researched it myself; not a guru, though...