[chevyresto1]

I have a rear end we thought was a first generation camaro. the # on the passenger side front of axel is phg 72041. the gears are 256. other # on the carrier housing is G1566.this is a multi leaf spring rear. any help is appreciated.

[66GMC]

According to http://www.nastyz28.com/camaro/zsusp.html ...

"PH" was a 3.55:1 ratio locking diff.
Used in '67 / '68 according to the drop-down

"G1566" = July 15, 1966? (Not sure about that)

Rear Housing Casting Date
Example: D141 - (D = Month, 14 = Day, 1 = Last digit of year (1971)).

Month: A = Jan, B = Feb, C = Mar, D = Apr, E = May, F = Jun G = July, H = Aug, I = Sep, J = Oct, K = Nov, L = Dec

TheCamaro.com has an "axle de-coder" that confirms the ratio, and says it was built on Aug 20.

FirstGenCamaro.com has differing information.

IMO, the safest way to correctly identify the gear ratio and carrier type is to remove the cover and have a look. Divide the number of teeth on the crown gear by the number of teeth on the pinion. There are tons of places on the internet that will identify the axle size/family visually by the number of bolts on the cover, etc. Richmond Gear for one.