66 Differential Code
Thread Starter
Le Mans Master
Joined: Sep 2003
Posts: 8,812
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From: eastern NC
66 Differential Code
We have a rear end that is currently in a '69 427/390, 4-speed coupe.
The code on the bottom of the differential reads AZ 2 24 66
It has a casting number on the forward passenger side (pinion) of the housing that reads 3876476-N. It does not have posi.
Based on a search of the archives, it appears to be a 3:55, from a 66 originally. (Thanks to everyone for all of the useful data there, what a terrific resource you've given us.
)
Can someone tell me exactly what this originally came from, big block or small block. If it's from a big block car, should it be non-posi?
Thanks for the help... GUSTO
The code on the bottom of the differential reads AZ 2 24 66
It has a casting number on the forward passenger side (pinion) of the housing that reads 3876476-N. It does not have posi.
Based on a search of the archives, it appears to be a 3:55, from a 66 originally. (Thanks to everyone for all of the useful data there, what a terrific resource you've given us.
)Can someone tell me exactly what this originally came from, big block or small block. If it's from a big block car, should it be non-posi?
Thanks for the help... GUSTO
Thread Starter
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Since it's obviously not original to the car and doesn't have posi, that's an option. We have a couple of extra rears to choose from that have posi, but they may require rebuilding and this one is in excellent shape and really needs nothing.
I was trying to determine if it should have the posi since it is a 427 and if in fact it is the heavy duty rear. Since it doesn't have cap screw yokes (it has the u-bolts now) I'm wondering if it is a BB rear, or if it's possible someone changed out the side yokes in the past.
Thanks for the information so far, it's been a big help in deciding which way to go.
GUSTO
I was trying to determine if it should have the posi since it is a 427 and if in fact it is the heavy duty rear. Since it doesn't have cap screw yokes (it has the u-bolts now) I'm wondering if it is a BB rear, or if it's possible someone changed out the side yokes in the past.
Thanks for the information so far, it's been a big help in deciding which way to go.
GUSTO
Race Director
Joined: Jul 2002
Posts: 11,593
Likes: 173
From: Clayton NC
Got it, I'm just looking for a spare pumpkin I can rebuild. I was hoping that it did have the BB style yokes. The last aftermarket BB yokes I ordered were JUNK. Email me if you decide to sell one of the ones you have. Dave
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,925
From: Washington Michigan
Originally Posted by GUSTO14
I was trying to determine if it should have the posi since it is a 427 and if in fact it is the heavy duty rear. Since it doesn't have cap screw yokes (it has the u-bolts now) I'm wondering if it is a BB rear, or if it's possible someone changed out the side yokes in the past.
Thanks for the information so far, it's been a big help in deciding which way to go.
GUSTO
Thanks for the information so far, it's been a big help in deciding which way to go.
GUSTO
Thread Starter
Le Mans Master
Joined: Sep 2003
Posts: 8,812
Likes: 2,029
From: eastern NC
Originally Posted by JohnZ
It was originally a big-block 3.55 Posi, but somewhere along the line the yokes have been replaced with small-block yokes; the rest of the internals are identical between SB and BB diffs - only the yokes make the distinction between the two.
I was hoping you would comment and this confirms my suspicions. It will make the final decision much easier.
GUSTO
