I have looked at other posts here and am stumped. I have this chevy rear, 3894939 kf 3:55 posi, I pulled out of a '71 pontiac lemans over 15 years ago. it's the shorter rear ( pulled an axle and compared it with other axles I have out of the later rears) and it is shorter, plus I measured backing pate ect.. weird thing is the date code is I 7 6 or 8 (sept. 7 1966 or 8 looks more like an "8" could be wrong though. It has the later (68 -72 ect.) spring perches also. So is this unusual for the date not to be a "7" in year and have the shorter axles and the 3894939 casting #?? I own a restoration shop, and have quite a few rears and was gong thru them and found this one. It's a very nice piece also, no pitting ect... I just started to clean it up, very nice original, thanx for any help!:confused:

I 7 6 is September 7, 1966. The 1967 Chevelle was in production by then, and the 939 12 bolt is known to be a 1967 Chevelle 12 bolt. No problem that I see. The 67 was the first year to use the same perches used on the 68 to 72 rear ends.