# Opinions on Limited slip diffs



## deanhickey (Apr 6, 2015)

Ready for the final stage on my drivetrain rebuild. I need to replace my LSD as she is a one leg beauty at this time. The gearing is 3.36.
there are a few different brands of units out there. Looking for opinions good and bad and pitfalls to avoid. Not looking for a locker as this will be a street machine. Any input is appreciated. Thanks in advance.


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## bigD (Jul 21, 2016)

Some like a clutch type rebuildable unit. Some don't.

Here's a cheaper clutch type.

eBay

Auburn makes a couple of different non-clutch type units. Eaton & Yukon make higher priced units. 

http://www.ronsmachiningservice.net/gm-8-2-bop-2/

This vendor sells all of these. So, it might be a good idea to talk to them & see what they have to say about it.


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## deanhickey (Apr 6, 2015)

bigD said:


> Some like a clutch type rebuildable unit. Some don't.
> 
> Here's a cheaper clutch type.
> 
> ...


Thanks for the links, Do you think increased cubes will have a major impact on these units, have bored the engine 0.040 over and stroked it to 4.25 this should give around 462 cubes and a decent increase in torque.


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## bigD (Jul 21, 2016)

If you ever plan to use sticky tires, ditch the 8.2. The pinion is too small for that amount of torque. 

You need a correctly built 8.5, 12-bolt, 9" Ford, or Dana 60, with HD axles & high quality parts.


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## deanhickey (Apr 6, 2015)

bigD said:


> If you ever plan to use sticky tires, ditch the 8.2. The pinion is too small for that amount of torque.
> 
> You need a correctly built 8.5, 12-bolt, 9" Ford, or Dana 60, with HD axles & high quality parts.


Just plan on using street/red line tires, but I do plan on smoking them a little.


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## bigD (Jul 21, 2016)

deanhickey said:


> Just plan on using street/red line tires, but I do plan on smoking them a little.


Since you're gonna spend several hundred bucks anyhow, this would be a good time to upgrade to something stronger. Not only safer for you, but should increase car value if you ever decide to sell.


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## deanhickey (Apr 6, 2015)

bigD said:


> Since you're gonna spend several hundred bucks anyhow, this would be a good time to upgrade to something stronger. Not only safer for you, but should increase car value if you ever decide to sell.


It's numbers matching drive train so I should set the original aside and put in a stout unit. Thanks for the advise.


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## geeteeohguy (Feb 2, 2008)

Big D is right on the money here. In 1990, I had the 3.55 cone type 8.2 unit in my '65 rebuilt by Larry Woltzen.....he installed 3.36 gears at my request and had a method of rebuilding the cone type unit. It's been just fine for the past 29 years, behind a stout tripower 389 and a 4 speed, and has seen a lot of spirited driving. To do it again, I would upgrade to a stronger rear end,though. My overhaul cost over $900 in 1990 dollars.....not cheap!


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## deanhickey (Apr 6, 2015)

geeteeohguy said:


> Big D is right on the money here. In 1990, I had the 3.55 cone type 8.2 unit in my '65 rebuilt by Larry Woltzen.....he installed 3.36 gears at my request and had a method of rebuilding the cone type unit. It's been just fine for the past 29 years, behind a stout tripower 389 and a 4 speed, and has seen a lot of spirited driving. To do it again, I would upgrade to a stronger rear end,though. My overhaul cost over $900 in 1990 dollars.....not cheap!


Thanks for the input, I will go for a stout diff. I am considering changing the gearing for a more highway friendly one. What are the other considerations I should look at?


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## geeteeohguy (Feb 2, 2008)

Big D already mentioned what rear ends to look at, depending on budget. For the $$$, the 8.5 can't be beat IMO. On gearing, I went from 3.36 in my '67 to 2.56 because a friend gave me the entire rear end (it was a limited slip, too!) for free. In my TH400 convertible with a mild 400, it is not optimal for hole shots, but can not be beat on the open road. 21mpg at a steady 80 mph.....all day long and running cool. Since the change, I have put a TON of miles on the '67 due to the increased fuel mileage and cruising comfort. Optimal all around automatic trans GTO rear end ratio, IMO, is a 2.93......and my favorite 4 speed car rear gear is a 3.23. A 3.08 is a great all around gear, as well. Driving these cars with a 3.55--3.36 gear is pretty rough in today's traffic.....you guzzle gas, run hot, and can't keep up with the Hondas.


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## deanhickey (Apr 6, 2015)

bigD said:


> If you ever plan to use sticky tires, ditch the 8.2. The pinion is too small for that amount of torque.
> 
> You need a correctly built 8.5, 12-bolt, 9" Ford, or Dana 60, with HD axles & high quality parts.


I have done a little more home work. the diff is a four pinion 3.36 Nodular housing( 9793235). So Have two more questions
1. Does this make any difference in strength ?
2. If I rebuild it does the 4 pinion make a difference in the rebuild kit?

I am probable over thinking things.:nerd:


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## PontiacJim (Dec 29, 2012)

deanhickey said:


> I have done a little more home work. the diff is a four pinion 3.36 Nodular housing( 9793235). So Have two more questions
> 1. Does this make any difference in strength ?
> 2. If I rebuild it does the 4 pinion make a difference in the rebuild kit?
> 
> I am probable over thinking things.:nerd:




Read this: https://www.gtoforum.com/f122/2-pinion-vs-4-pinion-123978/


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## deanhickey (Apr 6, 2015)

I have read that thread previously and it seemed a little inconclusive to my dilemma. What I am trying to achieve is a rear end that can handle the torque of the engine rebuild. Have stoked the engine out to about 456 ci. The cam is an 068. I know it is a mild cam for the cubes but I want it to be very street friendly. Thanks for the link.


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## dd68gto (Nov 14, 2012)

deanhickey said:


> I have read that thread previously and it seemed a little inconclusive to my dilemma. What I am trying to achieve is a rear end that can handle the torque of the engine rebuild. Have stoked the engine out to about 456 ci. The cam is an 068. I know it is a mild cam for the cubes but I want it to be very street friendly. Thanks for the link.[/QUOTE
> 
> I have a strong 400 street motor . It's around 360 hp and 450 lbs of torque all coming in early making for a great street car. It's s 68 convertible with the 400 turbo tranny . I am running the peg leg 2.93 gears and love them . I'm looking to up grade to posi but I would never change my 2.93 gears which is difficult with the rearend I have . I had a trans am with the 4 speed with 3.08 and that also was a perfect gear with the manual . I really don't think you will have any issues if it a streets car that you just want to smoke the tires. If you stay away from sticky tires you will be fine. My issue is the 2.93 and the carrier which limits me in upgrading to Posi. I smoke my tires on every chance I can you can't beat that Pontiac torque . . Doug


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## deanhickey (Apr 6, 2015)

dd68gto said:


> deanhickey said:
> 
> 
> > I have read that thread previously and it seemed a little inconclusive to my dilemma. What I am trying to achieve is a rear end that can handle the torque of the engine rebuild. Have stoked the engine out to about 456 ci. The cam is an 068. I know it is a mild cam for the cubes but I want it to be very street friendly. Thanks for the link.[/QUOTE
> ...


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