66/67 Rearend - Pontiac GTO Forum
User Tag List

 2Likes
  • 1 Post By PontiacJim
  • 1 Post By varmit86
 
LinkBack Thread Tools Display Modes
post #1 of 8 (permalink) Old 06-12-2019, 03:15 PM Thread Starter
 
Join Date: Apr 2015
Posts: 11
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Garage
66/67 Rearend

hello all,
i am looking for some advice on the value of a rearend i am looking to sell, i bought this rearend in 1989 but never put it on my car, the information on the unit is listed below.
i do not have an idea of what it is worth in current condition:

late 66/ early 67 8.2 BOP posi- YH on drivers tube, 3:55 gearing.
date code=G146
8783393
55.5" backing plate to backing plate
28 spline axle
1971 ring & Pinion gear, 7/16 bolts with 11/16 head- 1.25 pinion nut.

the bolts were spot welded, not sure why see picture.
i know the highest value is to someone who would want the correct unit for their car, i just dont know what a cone style unit interest is anymore.

any input is appreciated
Attached Thumbnails
Click image for larger version

Name:	axle.jpg
Views:	69
Size:	1.08 MB
ID:	119533   Click image for larger version

Name:	date code.jpg
Views:	72
Size:	1.43 MB
ID:	119535   Click image for larger version

Name:	gto.jpg
Views:	71
Size:	1.40 MB
ID:	119537   Click image for larger version

Name:	ring gear.jpg
Views:	70
Size:	1.15 MB
ID:	119539   Click image for larger version

Name:	whole unit.jpg
Views:	72
Size:	1.10 MB
ID:	119541  

Shadetree Racing is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old 06-13-2019, 08:34 PM
 
PontiacJim's Avatar
 
Join Date: Dec 2012
Location: Gastonia, NC - Born & raised in Connecticut - 31 years
Posts: 3,739
Mentioned: 1 Post(s)
Tagged: 1 Thread(s)
Quoted: 404 Post(s)
Garage
Quote:
Originally Posted by Shadetree Racing View Post
hello all,
i am looking for some advice on the value of a rearend i am looking to sell, i bought this rearend in 1989 but never put it on my car, the information on the unit is listed below.
i do not have an idea of what it is worth in current condition:

late 66/ early 67 8.2 BOP posi- YH on drivers tube, 3:55 gearing.
date code=G146
8783393
55.5" backing plate to backing plate
28 spline axle
1971 ring & Pinion gear, 7/16 bolts with 11/16 head- 1.25 pinion nut.

the bolts were spot welded, not sure why see picture.
i know the highest value is to someone who would want the correct unit for their car, i just dont know what a cone style unit interest is anymore.

any input is appreciated

Never easy to put a price on it. May be of interest for an original 10-bolt, but most serious engine/car builds will go with something that can handle bigger HP, like a 12-bolt or 9". Although for a '66-'67, it can be used in other years if originality is not an issue.

The 3.55's are a good gear, but it may not be a good gear for 70 MPH highway driving, so would be a great gear for local cruising.

Posi is a plus as long as it works and does not need a rebuild.

The welded nuts are what would cause me to pass on it. Why are they welded? Is the bolt hole stripped? Were the bolts coming loose? and why? But someone else may just run it and take a chance.

You could bring it to a shop that rebuilds rear ends and have then try to disassemble it and inspect it to make sure no issues, and then re-assemble it so you know it is a good unit - which may help sell the rear end at a higher price.

So as with all things, go high at first and see if you get any bites or interest. I might start with $500 and drop down from there. Personally, because I am cheap, I think $250 range a more fair price and something that someone might take a chance on.

Just my opinion.
PontiacJim is offline  
post #3 of 8 (permalink) Old 06-14-2019, 10:41 AM
 
michaelfind's Avatar
 
Join Date: Dec 2018
Location: Waco, Texas
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
I have been running a similar rear end for many years and have honestly been very rough on it. Many, many hard accelerations through the years. I actually have three of these rear ends. Only one is the 3.55 with the posi unit. Is there any way to rebuild these so that they are somewhat comparable in strength and durability to a 12 bolt rear end? Although mine is not original for my 65 GTO, I like that it has a stock type appearance and would like to keep that appearance if possible. I actually have the original 65 rear end, but it is not even a positrac. I've considered rebuilding it to regain that extra inch or so of clearance at each fender well, but I think even the shorter axles are harder to locate these days. Rebuilding it might be an expensive adventure in frustration.

Suggestions? or has this already been tried through the years and proved to be a waste of time and money.

Thanks
Michael
michaelfind is online now  
 
post #4 of 8 (permalink) Old 06-14-2019, 10:56 AM
 
michaelfind's Avatar
 
Join Date: Dec 2018
Location: Waco, Texas
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
One more thing. Now that I look at your pictures more closely, you do not have the coil spring center holder, just the flat mount spot. I believe that makes it a 66 rear end at the latest. They needed the "hold down clamp" to keep the spring in place. For originality purposes, that may make it more valuable to someone.
michaelfind is online now  
post #5 of 8 (permalink) Old 06-14-2019, 06:55 PM
 
PontiacJim's Avatar
 
Join Date: Dec 2012
Location: Gastonia, NC - Born & raised in Connecticut - 31 years
Posts: 3,739
Mentioned: 1 Post(s)
Tagged: 1 Thread(s)
Quoted: 404 Post(s)
Garage
Quote:
Originally Posted by michaelfind View Post
I have been running a similar rear end for many years and have honestly been very rough on it. Many, many hard accelerations through the years. I actually have three of these rear ends. Only one is the 3.55 with the posi unit. Is there any way to rebuild these so that they are somewhat comparable in strength and durability to a 12 bolt rear end? Although mine is not original for my 65 GTO, I like that it has a stock type appearance and would like to keep that appearance if possible. I actually have the original 65 rear end, but it is not even a positrac. I've considered rebuilding it to regain that extra inch or so of clearance at each fender well, but I think even the shorter axles are harder to locate these days. Rebuilding it might be an expensive adventure in frustration.

Suggestions? or has this already been tried through the years and proved to be a waste of time and money.

Thanks
Michael

Nope, you won't be able to build it to match a 12-bolt. I've hammered on them pretty hard as well and not blown one up. The issues arise when you have the posi and you go with wider/stickier tires that grab. If you have "skinnies" or even the single legger, you are better off because the tires will break loose rather than bite and put all the torque through the rear-end.

The 8.5 10-bolt can be built to handle as much as a 12-bolt. These are 1971 and 1972 A-body cars. They are found under many other years, but you would want an A-body rear. I read that Pontiac still used the 8.2 in '71-'72. Several drag racers I know use the 8.5, one under a BB Nova.

To build one up would still cost you. Trying to find an original 12-bolt is not cheap. So aftermarket is the best option and just be done with it, all new and no worries.
deanhickey likes this.
PontiacJim is offline  
post #6 of 8 (permalink) Old 06-18-2019, 02:51 PM
 
michaelfind's Avatar
 
Join Date: Dec 2018
Location: Waco, Texas
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Quote:
Originally Posted by PontiacJim View Post
Nope, you won't be able to build it to match a 12-bolt. I've hammered on them pretty hard as well and not blown one up. The issues arise when you have the posi and you go with wider/stickier tires that grab. If you have "skinnies" or even the single legger, you are better off because the tires will break loose rather than bite and put all the torque through the rear-end.

The 8.5 10-bolt can be built to handle as much as a 12-bolt. These are 1971 and 1972 A-body cars. They are found under many other years, but you would want an A-body rear. I read that Pontiac still used the 8.2 in '71-'72. Several drag racers I know use the 8.5, one under a BB Nova.

To build one up would still cost you. Trying to find an original 12-bolt is not cheap. So aftermarket is the best option and just be done with it, all new and no worries.
Thank you for the facts. I suspected as much. I guess a new aftermarket unit will be my long term plan if I ever destroy this unit I am running. As I was investigating the differential currently under my car, I think I have discovered that I at least have the best of options for the year differential I bought many years ago. I was always told it was out of a 69 judge but had no verification. There is an N on the front of the snout. The casting codes on the center unit are 353 above 9795084. The axle housing has 008XH. From what I read at Wallace racing and in the Pinion Head posts you linked to, this is likely a Nodular iron housing with the 4 pinion set up. If that's correct, then the rear differential may live as long as I do. I do not plan to put slicks under this car. Will just smoke both rear tires most of the way down the track!
michaelfind is online now  
post #7 of 8 (permalink) Old 06-18-2019, 08:35 PM
 
PontiacJim's Avatar
 
Join Date: Dec 2012
Location: Gastonia, NC - Born & raised in Connecticut - 31 years
Posts: 3,739
Mentioned: 1 Post(s)
Tagged: 1 Thread(s)
Quoted: 404 Post(s)
Garage
Quote:
Originally Posted by michaelfind View Post
Thank you for the facts. I suspected as much. I guess a new aftermarket unit will be my long term plan if I ever destroy this unit I am running. As I was investigating the differential currently under my car, I think I have discovered that I at least have the best of options for the year differential I bought many years ago. I was always told it was out of a 69 judge but had no verification. There is an N on the front of the snout. The casting codes on the center unit are 353 above 9795084. The axle housing has 008XH. From what I read at Wallace racing and in the Pinion Head posts you linked to, this is likely a Nodular iron housing with the 4 pinion set up. If that's correct, then the rear differential may live as long as I do. I do not plan to put slicks under this car. Will just smoke both rear tires most of the way down the track!


Perfect. I'd run it till it popped if it were mine because it would be worth more to me to use it myself and take my chances than selling it and then having to replace it with a higher cost rear axle assembly. I would work on plan "B" - getting the homework done should you ever need a beefier rear-end just so you have a rough idea of pricing.

It's almost easier to buy a complete & set-up rear end than to locate something, have it torn down, purchase the "good" parts, then get it all set-up again with new parts going into a used housing. I opted for a Ford 9" set-up for the GM A-body. Bolted right up. Reason I opted for the 9" is that they have been around forever, and are under everything from stock, to hot-rods, to drag cars and are still popular today. Parts are easily available and probably will be long after I am dead. 12-bolts....I don't quite see the longevity in them.

You can also build a different center section with another gear ratio if you want to play around. Once it is set-up, no further playing around with pinion depth or gear meshing as its all done when the center housing holding the gears is set-up. Then all you do is pull axles, and unbolt and bolt back in the other set of gears, and slide in the axles. Gives you the option of highway gears if you went on a long trip, around town gears, and all out drag strip gearing if you were so inclined.
PontiacJim is offline  
post #8 of 8 (permalink) Old 06-19-2019, 07:52 PM
 
varmit86's Avatar
 
Join Date: Nov 2009
Location: Washington
Posts: 10
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by michaelfind View Post
I have been running a similar rear end for many years and have honestly been very rough on it. Many, many hard accelerations through the years. I actually have three of these rear ends. Only one is the 3.55 with the posi unit. Is there any way to rebuild these so that they are somewhat comparable in strength and durability to a 12 bolt rear end? Although mine is not original for my 65 GTO, I like that it has a stock type appearance and would like to keep that appearance if possible. I actually have the original 65 rear end, but it is not even a positrac. I've considered rebuilding it to regain that extra inch or so of clearance at each fender well, but I think even the shorter axles are harder to locate these days. Rebuilding it might be an expensive adventure in frustration.

Suggestions? or has this already been tried through the years and proved to be a waste of time and money.

Thanks
Michael
I do have a late 65 production date YH out of my 66 it is original and untouched from a low mile GTO that has been in my family since day one. I am looking for someone looking for a period correct untouched rear end so I can get good money out of mine or I will just hold on to it. I know when you need something original it always cost BIG dollars and your happy to find it.
So if it is a super nice part and your patient you can get good money for it and not have to sell it for scrap.

There is someone looking under the wanted section for early 67 rear end
michaelfind likes this.
varmit86 is offline  
Sponsored Links
Advertisement
 
Reply

  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Undercarriage, Frame, Transmission and Differential Discussions.

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Pontiac GTO Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome