mfpm7232

I'm told this is a corporate 10-bolt (8.5") from a '72 Cutlass. I believe it's open with 2.73? gears. I'm just looking for confirmation it is what I'm being told as I'm interested in buying it to replace my 'O' type in me '69 Cutlass. How can I confirm? Also the asking price is $250. Is that a reasonable price?

Thanks in advance for any help!
Mark

brddg

Looks like it. But I would never pay that much for such a janer. Why the need to replace?

J-(Chicago)

Lousy picture, but it does look like an 8.5 to me. and with the shocks being rearward of the axle tubes, it's probably a 71-72

J-(Chicago)

$250 is a reasonable price for a rear end in good working order. I'd try to get it cheaper though since those gear ratios aren't the most desirable.

2blu442

Look for the code stamped in the passengers side axle tube. You might have to work it over with a wire brush or sandpaper, but that can show exactly what the application was. I agree with J, in my part of the country the rear end would sell for closer to $100 with the 2.73 open.

John

mfpm7232

Thanks guys for the advice. I was thinking it was a bit overpriced. I haven't seen it yet aside from the pathetic photo the seller sent me. I don't have a lot of confidence in the seller either. I may hint it's only worth about $125 and see how he responds. I'm in no hurry to buy either so I'd be happy to move on to the next one I see. This one looks like a total overhaul to me based on the picture.

I imagine a new 3 series posi, 3.42 gears and a rebuild kit plus install labour will cost about $800 or so. Sound about right?

507OLDS

It does look like an 8.5" 10-bolt,from a 71-72 Cutlass/442. Caution,those aftermarket chrome covers also fit the 8.2" Chevy 10-bolts,so don't go by what cover is on it.

mfpm7232

Great point Brian - I didn't know that. Something I'll be sure to watch out for.

I decided against pursuing this rear end - partly because of condition and price. The seller would go below $200 and that seemed too much considering the work involved.

With your recent post about possible gears from Richmond for the type "O" Brian, it's got me rethinking my pursuit of the corporate 8.5". Would I be better off getting gears if/when they become available? It sounds like I'd also need spacers to fit my 2 series carrier. Is it possible to change an open diff to a posi or must I buy a new a whole new carrier?

I appreciate everyone's advice on this!!

Thanks
Mark

507OLDS

You always need to look at the final cost,when the smoke clears,to see what is the most practical option.
In the past,when gears were available for the O-axle,I was selling complete kits,with a new posi,new gears,all new bearings & seals,and a complete installation kit,for $950.00.
If you are having a shop do the install,you need to add their cost on top of that.
I sell my complete,rebuilt 71-72 8.5" 10-bolt rears for $1100.00 plus the freight.When you swap from an O-axle to the 8.5" 10-bolt,you need to shorten your driveshaft,so there is that cost,plus the cost of freight,to consider for that swap.

mfpm7232

Yes, cost is always an issue - at least for me anyway...

I'd be okay with using my type O but I guess all parts (bearings, seals, etc.) are hard to find as well? Do you think they'd also produce the kits along with the gears?

Also, could I change my current open diff into a posi or is a carrier swap required? A swap of course would drive up the cost a fair bit.

If the type O gears don't happen then at least I still have an option to pursue with the 8.5. Maybe best to wait and see for now.

507OLDS

If you can wait,I would,just to see I the gears are available in the spring. The gears are the only hard part to get. All of the bearings are readily available,and new posi units are too.
If you want a simple posi swap,with your existing gears,you can install a PowerTrax 1920LR unit into your existing 2-series carrier,for under $350.00,and it is easy enough that you can do it yourself.The gears and everything stay in place.Just remove the spider gears and side gears in your non-posi unit,and install the PowerTrax unit in place of them.

brddg

How much do you need to shorten the driveshaft for that conversion?

mfpm7232

Hey, that's great info Brian. Considering the gears are the hard part, it does make sense to wait. I'm in no rush - car is in hibernation anyway.

Come spring if I find the gears are available, I may look you up to set me up with the rest of the stuff. If you're in Erie, you're just a couple hours away and my wife love's to shop at the mall. That will give me some brownie points for the spend on 'the car'.

Thanks for your help and expertise!

monzaz

I have a few of these units no box deal 299.00
1920LR 28 spline

10.00 bucks shipping.

61reoldsman

Is this Powertrax unit just for drag racing ?or is it a street unit too?

507OLDS

Actually,I would NOT recommend this for drag racing,just occasional strip use,or street.A little ratchety/clicky when cornering,but not clunky or choppy like the 60's Detroit Lockers.

monzaz

If installed correctly (which people tend NOT to read the instructions well these days....lol. ) It will perform well in all applications. Obviously if you were drag racing every weekend and are a 12 sec and faster car....you should think about full spool territory- unless you can tune your own posi units and keep them up to the task of the beating on the track.

These units usually solve a problem with no posi and you like your gears situation. The harder you accelerate the better the unit stays engaged. They have a different more expensive model called the NO SLIP which only clicks one full revolution of the tire instead of every tooth like this one. Price difference is substantial that more people by the Lock Right over the NO SLIP.

Jim