# posi-rear



## sixtysix (Jul 2, 2010)

my 66 goat has a standard rear with a 3:08 ratio, I am thinking about changing over to a posi rear or a safe-t-trac. what do I need to do to make the change? dooes any one have the parts needed and is it expensive?

66


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## dimitri (Feb 13, 2009)

I have a Richmond Gear with a Auburn Gear Posi unit. I am really happy with them. If you go to WELCOME TO RICHMOND GEAR this website has a gear calculator you can use. It will calculate rear gear ratio for a given rpm and speed. It's fun to play with. You will need to know your tire diameter in inches.


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## sixtysix (Jul 2, 2010)

will any 10 bolt gm posi rear set up fit?


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## dimitri (Feb 13, 2009)

Yes it will


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## geeteeohguy (Feb 2, 2008)

Yes and no. If you change the whole thing: carrier, ring, pinion, etc., no problem. If you try to install a GM posi unit to your 3.08 carrier, you need a "3-series" carrier. There are several different ones, and due to ring gear thickness diferences, they won't interchange. I would do the Auburn conversion and keep the 3.08s...it's a great ratio, especially with $5 gas coming!!! 10 bolt carriers: 2 series (2.56-2.78 gears), 3 series (2.93-3.23 gears) 4 series (3.36-4.33 gears).


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## BearGFR (Aug 25, 2008)

sixtysix said:


> will any 10 bolt gm posi rear set up fit?


Yes, as long as it's for an A-body car (GTO, Lemans, Tempest, Cutlass, 442, Skylark, GS, Chevelle...)

Also part way through the 1967 model year there were some small changes made to the upper control arm mount points and also the overall brake-to-brake axle width. The later style will still work in your 66, in that all the spring mounts will line up, but you might have to do some minor parts swapping and use wheels with a slightly different back-space, depending on "how much tire" you're trying to fit under the car.

Unless you're insistant on keeping a 100% "bone stock" appearance, I always recommend replacing the factory upper rear control arms with adjustable ones. Having that adjustability enables you to make sure your axle pinion centerline is parallel with your transmission/crank centerline. If it's not, you'll tend to get a mysterious and very annoying vibration.

Bear


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## 66tempestGT (Nov 28, 2009)

so i can put 10 bolt chevy carrier in a 10 bolt pontiac housing?


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## geeteeohguy (Feb 2, 2008)

Not from what I've seen....Just BOP carriers. Chevy applications have C-clips to hold the axles in place......


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## BearGFR (Aug 25, 2008)

geeteeohguy said:


> Not from what I've seen....Just BOP carriers. Chevy applications have C-clips to hold the axles in place......


Yeah? I didn't realize that --- I thought the c-clip stuff was unique to 12-bolts - shows what I (don't) know... 

Bear


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## geeteeohguy (Feb 2, 2008)

A lot of different rear ends, a lot of different configurations..gets confusing. Yes, the Chevy 8.2 ten bolt has C-clips, and also has smaller diameter axles with less splines than the BOP unit, and a smaller pinion as well. Not as strong as the BOP, and the BOP's aren't the strongest units out there...... I have read elsewhere that a BOP 8.2 unit will handle up to 500+ HP if not abused heavily, tho'......


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## 646904GTO (Feb 10, 2008)

geeteeohguy said:


> A lot of different rear ends, a lot of different configurations..gets confusing. Yes, the Chevy 8.2 ten bolt has C-clips, and also has smaller diameter axles with less splines than the BOP unit, and a smaller pinion as well. Not as strong as the BOP, and the BOP's aren't the strongest units out there...... I have read elsewhere that a BOP 8.2 unit will handle up to 500+ HP if not abused heavily, tho'......


I know for a fact they won't, or maybe it was just abused heavily, lol.


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## geeteeohguy (Feb 2, 2008)

I've blown up my share with a heck of a lot less than even 350HP!!! Being young helps.....spectators help....and "other" factors......'nuff said.


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## 66tempestGT (Nov 28, 2009)

i had a 10 bolt rear once that i was told was from an oldsmobile. it was physically larger than my pontiac. it needed a shorter driveshaft. everything else bolted right in.


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