65 Rear end date code

[Tim S.]

Can anyone tell me how far out (prior) a date code for a differential can be? This is for a 2nd week Jan 65. Here's the twist, my car originally had 4.56's....code AQ. Due to the fact 4.56's were sparse to begin with, does anyone have examples to share?

Thanks,
Tim

[Jack H.]

Re: 65 Rear end date code

Date code judging guideance is given in the Judging Guide and Standard Deduction tables of the Judging Reference Manual. If a given part isn't listed (JRM) or guidance isn't cited (JG), then the standard NCRS policy is for dated parts to fall within a 0-6 month interval prior to the car's final assy date.

[Wayne M.]

Re: 65 Rear end date code

.... Due to the fact 4.56's were sparse to begin with, does anyone have examples to share? ..Tim

Here's an example at the other end of the ratio spectrum [3.08 posi]. P-o-P imprint on dealer work order for '65 # 04385 with L79; (may be still kicking around eastern Ontario). Birthday book says reached final assembly on or about 18th Dec.

Now the power train charts say 3.08 posi was not even available with L79, but the dealer showroom brochure says yes (3.08 thru 4.56), just like L76 and L84.

IMO, the 9th of Dec for the posi assembly is really tight; however I don't think this pumpkin was nearly as rare as the 4.56 set. I can't make sense of the G81 table in Noland's Vol 2, pg 271 --- what's the difference between 3.08 posi with L76 and L84 (368 units) versus 3.08 posi with G91 ??? [always though that RPO meant 3.08 w/o posi] and 4-sp wide ratio (base motor and L75) @ 1710 units ?

Note the extreme gap between the trans assy Aug 29th and Dec 18th final. Probably affected by the strike and the rare close ratio coupled with low numerical speedo drive gear.

Hope all this hasn't muddied the waters.