# Chevy posi identification help

**URL:** <https://forums.speedlife.net/t/chevy-posi-identification-help/36170>\
**Category:** NYSpeed Automotive\
**Created:** [September 29, 2007, 9:33pm UTC](https://forums.speedlife.net/t/chevy-posi-identification-help/36170 "2007-09-29T21:33:34Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Camaro079](https://avatars.discourse-cdn.com/v4/letter/c/d6d6ee/32.png) [@Camaro079](https://forums.speedlife.net/u/Camaro079)\
**Post date:** [September 29, 2007, 9:33pm UTC](https://forums.speedlife.net/t/chevy-posi-identification-help/36170/1 "2007-09-29T21:33:34Z")

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i picked up an old posi unit at a garage sale for cheap, but i dont know what it fits and would appreciate some help. it has “GM1” “410409N” “B24”(which i think is the date code) and “66”(either 66 or 99 spaced out). It has the old style ‘S’ spring between the spider gears. the lady at the sale had no idea what it fit since it was her husbands and he wasnt there. i thought maybe chevelle since they are fairly common, but i have no experience when it comes to identifying differential sizes. thanks for any help!

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**Author:** ![vt1992s10](https://avatars.discourse-cdn.com/v4/letter/v/73ab20/32.png) [@vt1992s10](https://forums.speedlife.net/u/vt1992s10)\
**Post date:** [September 29, 2007, 10:09pm UTC](https://forums.speedlife.net/t/chevy-posi-identification-help/36170/2 "2007-09-29T22:09:02Z")

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8.5 Corporate 410409N series 2 2.56:1 and down

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**Author:** ![joelster](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/joelster/32/7258_2.png) [@joelster](https://forums.speedlife.net/u/joelster)\
**Post date:** [September 30, 2007, 5:58am UTC](https://forums.speedlife.net/t/chevy-posi-identification-help/36170/3 "2007-09-30T05:58:20Z")

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I doubt it’s a posi if it’s got 2.56 gears or worse.

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**Author:** ![psychopjv](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/psychopjv/32/7251_2.png) [@psychopjv](https://forums.speedlife.net/u/psychopjv)\
**Post date:** [September 30, 2007, 6:33am UTC](https://forums.speedlife.net/t/chevy-posi-identification-help/36170/4 "2007-09-30T06:33:44Z")

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[http://www.wallaceracing.com/carrier-id.html](http://www.wallaceracing.com/carrier-id.html)  
BAM!

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**Author:** ![joelster](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/joelster/32/7258_2.png) [@joelster](https://forums.speedlife.net/u/joelster)\
**Post date:** [September 30, 2007, 6:59am UTC](https://forums.speedlife.net/t/chevy-posi-identification-help/36170/5 "2007-09-30T06:59:49Z")

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Well, there you go, lol.