I have a '67 camaro 10 bolt rear axle, wondering about putting a aftermarket posi unit in it. The code on the gear with the cover removed reads: 1 GM 3790629 12 37 10 67. What gear ratio is this? Thanks in advance for any help you can provide. Steve:)

37/12=3.08

I would purchase and install an Eaton 3 Series Posi Unit. In addition to being rebuildable, it is a very durable unit.

Like BGH says, the "12" and "37" in that string of numbers refers to the tooth count on the pinion (12) and ring gear (37), so the ratio is 37/12 = 3.08

As far as whether it's worth dropping in an aftermarket posi, I think "we" need more info to give you good advice.

What engine and trans are you running?
Any plans to run at the drags?
Any plans for drag slicks or drag radials (or just street tyres?)

The stock '67 rear would be an 8.2" 10-bolt, which isn't super-strong in stock form. If you're looking at a driver on street tyres, it'll hold up fine, but probably not the best choice for a car with a big block and race tyres that sees a lot of track time...

A 8.5 10 Bolt is very durable and cheaper alternative than a 12 Bolt if you feel the 8.2 will not be strong enough for your needs.

The stock '67 rear would be an 8.2" 10-bolt, which isn't super-strong in stock form. If you're looking at a driver on street tyres, it'll hold up fine, but probably not the best choice for a car with a big block and race tyres that sees a lot of track time...Agree, but I have clocked over 900+ 1/4 mile runs with a thin ring gear 4.11 and a spacer turning a pair of 28.5X10.5 slicks before the carrier split in two. So, there is some strength to it.

Maybe its angel was following behind.............

Thanks for all the responses. It is nice to know the gear ratio info and I appreciate you guys' assistance on what I should do. As far as more details on the car , it is a '67 RS Camaro with a stock Muncie 4-speed. I think the car originally came with a 6cyl. according to the firewall numbers. The engine is a '78 Corvette 350. with aluminum intake and 4barrell.
I agree that an Eaton 3 series posi would work well, but do you think the rear end will handle the 350? I am probably not going to race it, and would be running street tires-(BF Goodrich radial TA's). Right now with this gearing, it revs pretty good going down the interstate.

If you are not going to drive the car hard, the 8.2 will be fine. If you are thinking about taking the Camaro down the track, go with a 8.5.

The 8.2 with the Eaton posi will hold up as long as you keep street tires on it and keep wheel hop under controll. If you need a price on the Eaton let me know. You will also need bearings and shims to set it up.

That's relatively low hp 350 engine IF it is stock so you should be fine like Freddie says.

You up it's compression and start adding speed equipment in and on it and an 8.2 isn't going to last long especially w/ some good traction!!

pdq67

With a 350 and street tyres, I'd drop in an Eaton posi and run that 8.2" without any worries at all. I'd also recommend thinking hard about whether you want to change your rear gears or not. I'm not saying there's anything wrong with the 3.08's (I'd think they probably work pretty darn well for a driver) it's just that it'll be a bit easier to swap gears while you have the rear apart already. (I hate tearing back into something that I've already had apart....)

Agree, but I have clocked over 900+ 1/4 mile runs with a thin ring gear 4.11 and a spacer turning a pair of 28.5X10.5 slicks before the carrier split in two. So, there is some strength to it.

Maybe its angel was following behind.............

Yup -- 8.2's can certainly be made to live behind "big torque", but I figure anyone that currently has an open 8.2" and knows they're gonna do a bunch of track time is probably better off dropping an extra $100-$200 on an 8.5" first rather than throwing $500 or so on a posi for the 8.2"

At least, if it were me, it'd be worth the extra $ for piece of mind. (Of course, if you already have an 8.2" posi and plan to hit the track, I'd probably run it until it dies)

In any case, I think the OP will be fine with the 8.2"

Yup -- 8.2's can certainly be made to live behind "big torque", but I figure anyone that currently has an open 8.2" and knows they're gonna do a bunch of track time is probably better off dropping an extra $100-$200 on an 8.5" first rather than throwing $500 or so on a posi for the 8.2" No doubt, agree.

At least, if it were me, it'd be worth the extra $ for piece of mind. (Of course, if you already have an 8.2" posi and plan to hit the track, I'd probably run it until it dies)I did, then bought a 12-bolt and rebuilt it. They were still affordable then, $300 complete plus parts, shims, bearings, clutch packs, were under $100. Oh, added C-clip eliminator also.

What type of rear gears would you recommend for this setup? Steve.

Richmond, or Freddie's suggestion of vendor.

Had a 8.2" I built with an Eaton posi,3.73's,and never an issue.

Get me a price on that posi setup when you get a chance.

I picked up a "half" finished 67. Worked 454, 4 sp, didn't get to the rear. Street tires all the time, I do drive pretty hard though.

If I read this right, the open 6 cy 10 bolt rear that is in it is not worth building?

Local guy owns a race shop and said for $1400 he could build it bullet proof. That sounds pretty stupid, but I have not found something that will bolt in for less than double. Thoughts?

Oh, and to help me in my search, what rears bolt in a 67? Using Global West leafs that use stock type mounting. Thanks, and I hope I didn't take away from the OP.

I'd like to see a bulletproof 8.2. :D The '67 to '69 Camaro, '68 to '74+ Nova and other X body car rear ends will fit. The 8.2 is the weakest, and most common. The 12 bolt is best and the 8.5 10 bolt is in between. The 8.5 can be built pretty strong, but requires replacing all of the internal parts. This can be done for the $1400 that the other guy wants to put into your 8.2.