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8.75 ... 489 ... what year?

Posted By: zrxkawboy

8.75 ... 489 ... what year? - 04/18/14 05:26 AM

I recently purchased an 8.75 rear out of a '66 Charger. However, it is a 489. From what I can find, these started production in '69. Since it was in (fit) the '66, I'm assuming this must have originally been in a '69 or '70 B-body. Is that right?
Posted By: RapidRobert

Re: 8.75 ... 489 ... what year? - 04/18/14 05:40 AM

I would assume it came from a mid 68 something (when the 489 intro'd) & since it has been changed out it would not have neccessarily have come from a B body
Posted By: zrxkawboy

Re: 8.75 ... 489 ... what year? - 04/18/14 05:49 AM

OK, I just thought that the distance between the perches changed for 71-74. That's why I thought it must be 69-70. So that's not right?

Edit: One of the posts I was referencing disappeared after I posted!
Posted By: dogdays

Re: 8.75 ... 489 ... what year? - 04/18/14 05:50 AM

Unless they were running short of 741 cases at some point, I would venture to guess that the 489 probably came behind a HP383, HP400 or any 440. Maybe 340s, maybe not every year's 340.

This is mostly a guess, but there are a lot of 741s out there, same as there are a lot of 318s and slant sixes. I've never seen one (489) behind a 318, although again, Mopar, never say never!

I'm sure someone else will clarify things.

R.
Posted By: Pacnorthcuda

Re: 8.75 ... 489 ... what year? - 04/18/14 05:53 AM

Lots of 489's were paired with 318's. Your center section may not be original to the housing, that's what makes things very hard to determine.
Posted By: Cab_Burge

Re: 8.75 ... 489 ... what year? - 04/18/14 07:54 AM

Quote:

I recently purchased an 8.75 rear out of a '66 Charger. However, it is a 489. From what I can find, these started production in '69. Since it was in (fit) the '66, I'm assuming this must have originally been in a '69 or '70 B-body. Is that right?

I'm almost positive your correct on the 489 cases being introduce into the production cars in mid 1969
Posted By: zrxkawboy

Re: 8.75 ... 489 ... what year? - 04/18/14 02:09 PM


Thanks, everyone, for the replies.

Quote:

Lots of 489's were paired with 318's. Your center section may not be original to the housing, that's what makes things very hard to determine.


True...I hadn't considered that the housing may have been original to the car. I guess it doesn't matter much, just more of a curiosity thing.
Posted By: RapidRobert

Re: 8.75 ... 489 ... what year? - 04/18/14 05:32 PM

Quote:

I'm almost positive your correct on the 489 cases being introduce into the production cars in mid 1969

Oh OK mid 69 not mid 68,
Posted By: 69CoronetRT

Re: 8.75 ... 489 ... what year? - 04/18/14 07:17 PM

Quote:

Quote:

I'm almost positive your correct on the 489 cases being introduce into the production cars in mid 1969

Oh OK mid 69 not mid 68,




Nope you were right the first time...the 489 was introduced during the 68 model year.
Posted By: TJP

Re: 8.75 ... 489 ... what year? - 04/18/14 09:12 PM

Quote:

Quote:

Quote:

I'm almost positive your correct on the 489 cases being introduce into the production cars in mid 1969

Oh OK mid 69 not mid 68,




Nope you were right the first time...the 489 was introduced during the 68 model year.



Posted By: 6bblgt

Re: 8.75 ... 489 ... what year? - 04/18/14 09:16 PM

what's the date stamped on the ring gear?
Posted By: John_Kunkel

Re: 8.75 ... 489 ... what year? - 04/18/14 10:57 PM

Quote:

Nope you were right the first time...the 489 was introduced during the 68 model year.



The factory parts book says January 9, 1968 was the introduction date for the 489 in some models and some ratios (2.76, 3.234 and 3.55 only).
Posted By: Pacnorthcuda

Re: 8.75 ... 489 ... what year? - 04/18/14 11:31 PM

Quote:

Quote:

Nope you were right the first time...the 489 was introduced during the 68 model year.



The factory parts book says January 9, 1968 was the introduction date for the 489 in some models and some ratios (2.76, 3.234 and 3.55 only).



Did early 489's come with power locks?
Posted By: John_Kunkel

Re: 8.75 ... 489 ... what year? - 04/19/14 12:44 AM


Apparently not...the parts book shows a new number for the open differential when used on the 1 7/8" but not the Sure-Grip.
Posted By: zrxkawboy

Re: 8.75 ... 489 ... what year? - 04/19/14 12:52 AM

Quote:

what's the date stamped on the ring gear?



Honestly, I'm probably not gonna take it apart for a while.
Posted By: 69CoronetRT

Re: 8.75 ... 489 ... what year? - 04/19/14 02:36 AM

Quote:

Quote:

what's the date stamped on the ring gear?



Honestly, I'm probably not gonna take it apart for a while.



Ok...then what's the casting date on the case?

Attached picture 8117043-Rear_end_450_casting_Date.jpg
Posted By: Pacnorthcuda

Re: 8.75 ... 489 ... what year? - 04/19/14 03:20 AM

Quote:


Apparently not...the parts book shows a new number for the open differential when used on the 1 7/8" but not the Sure-Grip.



So then there must have been a significant overlap of the 742 and 489s. I say that because recently i acquired a 742 with a power lock date coded June 18 68. Which wouldn't be surprising I guess. Raises the question; when did the 742 cease?
Posted By: zrxkawboy

Re: 8.75 ... 489 ... what year? - 04/19/14 03:26 AM

Quote:



Ok...then what's the casting date on the case?



Try as I might, I absolutely can't read it. I'm gonna pick up a grease crayon tomorrow at NAPA and see if that helps.
Posted By: John_Kunkel

Re: 8.75 ... 489 ... what year? - 04/19/14 06:28 PM

Quote:

So then there must have been a significant overlap of the 742 and 489s. I say that because recently i acquired a 742 with a power lock date coded June 18 68.



As I stated in my first post, "some models" got the 489 in '68...not all.
Posted By: zrxkawboy

Re: 8.75 ... 489 ... what year? - 04/28/14 12:34 AM

Just can't read the date code for anything. Oh well, doesn't really matter, I guess.

I did make another discovery today when I was out in the garage playing around. The diff has a 3.23 tag, but thought I'd make sure. Well, it is 3.23, but when I turned one side to count the turns, I found that the other axle was turning in the same direction! I was surprised, because I thought that if it was SG, the tag should say 3.23 S (it just says 3.23). Is that right? If so, hope I don't find a nasty surprise inside.
Posted By: John_Kunkel

Re: 8.75 ... 489 ... what year? - 04/28/14 08:00 PM

A Sure-Grip will usually have two tags, one with the ratio and one that advises to use SG fluid.

Attached picture 8127043-SGTag.jpg
Posted By: cudaman1969

Re: 8.75 ... 489 ... what year? - 04/28/14 10:52 PM

Quote:

Unless they were running short of 741 cases at some point, I would venture to guess that the 489 probably came behind a HP383, HP400 or any 440. Maybe 340s, maybe not every year's 340.

This is mostly a guess, but there are a lot of 741s out there, same as there are a lot of 318s and slant sixes. I've never seen one (489) behind a 318, although again, Mopar, never say never!

I'm sure someone else will clarify things.

R.


I have a 72 duster with /six three speed with a 489-323 limited slip factory installed.
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