Post up some photos of the rearend in question. The numbers 10 and 41 on the ring gear likely means 4.10 to 1 ratio.
Are the hubs full or semi floating? It's probably a 14 bolt or a Dana 60. Do a google image search for 14 bolt rear and Dana 60 rear and compare the results to what you have.


Steve

'49 3800
'52 3600
'57 3100