67 Camaro Series 3 Differential

[dans67camaro]

What is the correct series 3 casting number for a 67 - 12 bolt? I understand they can be either a Dana or Eaton unit. References have shown number 30140PM1 for a series 3, 3.08 to 3.73:1. I have located a unit with EDB30140 numbers. Which is correct? Thanks

[hotrod68]

I've never heard of a Dana under a '67 Camaro from the factory! Dana 60s were way different from the 12-bolt and were original in the (gaaacckkkk) Chryslers. I'm no numbers guru but I guess it's possible a Dana carrier could be in a 12-bolt if that's what you're asking. But the 3-Series carriers were different between a 3.08 and a 3.73. If memory serves me correctly, 3.73 and lower ring gears on a 3.08 carrier required a spacer plate because the pinion gear was so much smaller. I believe the thicker carriers that didn't need spacers started with 3.55s. But again, I know next to nothing about the casting numbers and am relying on memory. Hope this helps and good luck!

[dans67camaro]

According to my reference material, the series 3 carrier accomodates a 3.08 to 3.73 R&P. Series 2 accomodates 2.73:1 and down. Series 4 accomodates 3.90:1 and up. I have an EDB30140 pn, but there is no manufacturer casting logo. After the pn there is a "PM w/ a circle around it" cast in (raised) followed by the number "1". Could it be a corporate (ie GM produced)?

[JohnZ]

Chevrolet didn't manufacture Posi units - they purchased them; the "EBD" indicates that it's from Eaton, which was Chevrolet's sole source for Posi.

[hotrod68]

Thanks, dan--I remember now; A spacer was needed to go from a 3.73 to a 4.11 or lower gear until the aftermarket came out with the thicker ring gears. Zoom sold a lot of the spacer plates in the late '60s and early '70s!  lol  On the street factory Eaton 4-Series carriers were pretty rare, and everybody was running 4.11s or 4.56s--some hardcore guys even ran 4.88s and 5.13s. I ran 4.88s in my '64 Impala for awhile, but back then gas was only 32 cents a gallon.  Oh, those were the days!

[wonderdog]

Am curious if your EDB30140 is the old, original Eaton built posi.  Does it have the thick aluminum spring plates located UNDER the side gears???  Eaton aftermarket posi's have steel spring plates between the side gears.

[dans67camaro]

My unit does have steel plates between the side gears and springs. However, I believe it to be an original unit. How can I be sure?