Early 69 acceptable differential dates

[Joseph H.]

Hi everyone, still looking for a correct rear end for my sept. 68' 350/350 4spd. My question is what are the acceptable date ranges? I would assume (6 months) mar, apr, may, jun, jul and august of 68'? Also since I have no docs I would assume this car would have most likely come with a 3.36 or 3.55 gear ratio.

Thanks for all the help.

[Jack H.]

Re: Early 69 acceptable differential dates

According to MF Dobbins' Fact Book, the choice of rear end ratios for a '68 327/350 (the 350 SB engine didn't debut until 1969) varied with the 4-Spd tranny:

Wide Ratio (2.52): Std=3.36 Perf=3.55
Close Ratio (2.20): Std=3.70 Perf=4.11

Whoops! I read your post wrong...you asked about a '69 350350... Well, the factory ordering recommendations were the same as 1968 for the 350 HP engine.

[Joseph H.]

Re: Early 69 acceptable differential dates

Thanks and BTW I forgot the tranny info, I have a wide ratio. Still would like to know the acceptable date range, again I assume 6 months?

[Jack H.]

Re: Early 69 acceptable differential dates

I see no set aside provision to the 6-month rule for rear differential dating in my copy of the NCRS Judging Reference Manual. What's your copy say?

[Joseph H.]

Re: Early 69 acceptable differential dates

Mine indicates that since the juges cannot see the bottom of the diff then the dates are not judged. I guess what I am asking is in my quest for a "correct rear end" what dates would be a realistic range.

[Terry M.]

Re: Early 69 acceptable differential dates

Unfortunately, Joe, since we don't judge it -- there is no track record for differential dates. Your guess is as good as anyone elses.

[John C.]

Re: Early 69 acceptable differential dates

Joe

In Noland Adam's c2 restoration guide in the appendix he gives diff dates compared to vin numbers for 1967 cars. Most of the diff dates given are less than a month before the build date of the car. On my 68 the diff date is 3/27 and the car built date 4/18. On my 69 the diff date is 12/4 and the car build date is 12/11. Both my cars are BB. So it looks while the standard 6 month rule would apply if it were a judged item, in reality it was typically quite a bit less.

John

[Joseph H.]

Re: Early 69 acceptable differential dates

Thanks, that is what I wanted to know. I will keep that is mond during my quest.
Joe

[Greg L.]

Re: Early 69 acceptable differential dates

Just to reinforce what Joe said, the VAST majority of original dated components on my Jan 31/69 built car are dated some time in early to mid Jan. The earliest dated part would be my rear window which I think was July or Aug of 68.

I think the 6 month rule(12 months for glass) is the exception and not the rule.