Senior Tech Team
Join Date: Sep 1998
Location: Mustang, OK USA
Re: Question about 57 Chevy Rear
The 55-64 style rearend (also 56-62 Vette and 62-3 Chevy II) is really a good sturdy rearend if properly built, especially with some of the upgrades that are now available. An old, tired rearend that hasn't had much maintenance (if any) certainly isn't going to stand up to much abuse. Since this is a Chevelle site and not a full size Chevy site, most people here are probably not aware that this same style rearend was used behind 63-64 425hp-409 engines. AND, another thing that most of you don't know, is that the 63 with the RPO Z-11 pkg had this same rear with 30 spline axles instead of the standard 17 spline axles. This is my favorite rearend to rebuild (I've been doing these for over 40yrs) and as I said, they make a pretty stout rear. As mentioned, they are about equal to the 10bolt rears, and as many here know, a well built 10 bolt is fairly stout.
Also, as Freddie (Big Gear Head) mentioned, Eaton now makes a posi unit for these early rears. I've already installed a few for customers.
The gear ratios that were FACTORY available between 55-64 were: 3.08, 3.36, 3.55, 3.70 (NOT 3.73), 4.11, 4.56. At one time, you could buy 4.88, 5.13 and 5.36 gears from Chev parts dept. There never was (either from Chev or aftermarket) a gear higher than 3.08 for these early rears. In addition to the over the counter gears that Chev offered for these rears, they also sold extra thick ring gears for installation on a 3 series carrier. For example, this allowed conversion of a 3.08, 3.36, 3.55, etc to a 4.88 without having to install a 4 series carrier.
Oh well, gone are the good ole days of rearends that were easy to build!!! Right Freddie?
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