Date code meaning

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Aug 5, 2009 | 12:01 PM

CP64365

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From: PA

Date code meaning

For a muncie main case with casting number 3851325, which was use for 64 and 65 corvettes, the the date P0427 stands for April 27. Is there a way to tell if it was for year 64 or 65?

Thanks.

Aug 5, 2009 | 05:28 PM

sfbrown51

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From: S.I. N.Y.

The extension housing may help you. If the number is 3846429 it was made until 2/65. If the number is 3857584 it was made after 2/65. Thismight narrow it down for you. Also the assembly date code should be on the rear face of the maincase on the right side. I hope this helps.

Aug 5, 2009 | 06:48 PM

midstyle

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From: Calgary Alberta

Quote:

Originally Posted by CP64365

For a muncie main case with casting number 3851325, which was use for 64 and 65 corvettes, the the date P0427 stands for April 27. Is there a way to tell if it was for year 64 or 65?

Thanks.

Look at the top rear bolt boss on the maincase (where the bolt from the tail extension threads in). If it is square, it's April 1965; if round at the front end (like the bolt boss on the bottom of the maincase) then it's 1964. This change in casting happened around late Nov / early Dec 1964 on 325 maincases. That business about 429 tail extensions carrying on until Feb of 1965 is pure urban legend (unfortunately spread by A. Colvins book). 1965 Corvette tail extensions were "584"s from the start of 1965 model year Muncie production, in August of 1964.

Another way is to tell where the P0427 is stamped; if on the driver side cover, lower rear corner of the maincase (machined flat for stamping), then it is 1964 model year; if on passenger side edge of maincase, it's 1965.

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