Difference between an E-body and B-body rear end?

[BP23G0B]

How do you tell the difference between an E-body and B-body rear end?  I found a table at mymopar.com with a bunch of measurements for the different rears.  My rear seems square sice it has 6" of back space at each side.  This 8.75 isn't originally from my car and I thought it was strange I had so much BS.  I'd like to know if it came out of a B-body.  I'll measure it tomorrow and compare it to the chart I found, but is there a casting # that would tell me this? 

[Street_Challenged73]

I don't know where the numbers are located (if there even are any), but the B-body rear isn't as wide as an E-body's 8 3/4".   Perhaps Chryco, Rob, or FY1 will know the numbers for you.

[ShelbyDogg]

I've heard that they put numbers on the axle tubes but I've never found them on mine.  If you look at your  spring perches and they have the factory welds and your front and rear hangers are stock and not offset, then you have an e-body rear end.  The early b-body rear was narrower by 2" at the spring mount center to center AND the housing width so It won't fit your e-body springs unless the mounts were cut and rewelded or the springs were moved in.  You'll have to get under there and measure to be sure.
Rob

[Steve]

E-body:  60.70" Track with perches at 46" (center to center)
B (62-70): 59.20" Track with perches at 44"
B (71-79): 63.40 Track with perches at 47.3"

[BP23G0B]

Well, it's an E-body 8.75.  46" between the leafspring centerlines.  One less mystery.