I'm not really looking to see which one is "better." I have a car that is an auto and will probably never see racing slicks, so realistically either would work fine for me. What I don't have on the car right now is a posi.

I have a stock Type O 3.08 open axle in my '69 442, obviously I could just put a posi in that. I also have a Chevy 12 bolt housing from a 70 Chevelle, and an Eaton posi new in the box. The Chevy housing also has a set of stock axle shafts that are in unknown condition, although they don't have any obvious issues on a cursory inspection.

I'm trying to figure out what would be the best to do, put a posi in the Olds axle or do a build on the Chevy axle. I really have no preference as to which one goes under my car, so it's about the $$ and the convenience factor of building the Chevy axle while being able to drive on the stock one.

I think that in all likelihood the Olds would be cheaper to do, even with the cost of a posi unit, because of how much I could get out of the Chevy stuff if I sold it. I'd hate to sell the Type O as it is an original part for my 442.

I guess what I'm trying to figure is how deep I would be into the Type O vs. the Chevy to get one on the road. I'm happy with my 3.08s, so I would plan on reusing those. If I used the Chevy, I'd have to buy some gears, and I'd probably want used GM. The Chevy needs all the bearings, etc. and maybe axleshafts.

The Type O I'm not so sure about, it would be nice to just do a carrier swap, but I'm curious if anyone has any thoughts as to whether bearings will be a must for the pinion and the axleshafts if I go this route.

Both axles housings will need some clean up to be presentable. Any thoughts on rust removal/painting without totally taking the axle apart?

My guesstimate is that I'd be in the Chevy about $500 over what I have now if I used it. The fact is I could probably fund the Type O build by selling my Chevy stuff.

 

I would go with the O type just to be original. But I am a novice at this stuff.

 

Contact vendors on here to get a new posi unit along with rebuild kit & install it along with your original crown & pinion. You state that you are happy with the gear ratio so just add posi & carry on. This is what I did with my 69 442 that had a 3.23 open now converted to posi

 

Well it is your car - I can certainly help you price out parts for both if you like.

For the street both will do the job fine.

3.08 is a very good all around gear ratio.

Jim

 

my suggestion is to contact Brian Trick on here, extremely knowledgeable on rears.
His user name on here I believe is 507olds. Ask him everyone that I have talked to re: him has been extremely pleased. I have learned stuff just from reading his posts.

 

You could sell the 12-bolt Chevy housing and posi unit,buy a posi unit and all new bearings/seals to rebuild the entire O-axle,and still have money left over.
"IF" you needed gears for the O-axle,it would be a different story,as there really isn't much floating around out there right now.
Where are you located?

 

Attach.......

 

All of my car stuff is in the Phoenix area.

I'm leaning towards selling off my Chevy parts right now. The money end of doing things that way just makes too much sense not to do. I'll have to check the numbers on the housing to see it was anything special originally. Unfortunately, someone welded something onto the housing where the shocks mount. That said, with what I paid for the housing I'll be coming out ahead on it, anyway. I'll have to drag it out of my shed and see what I've got.

I won't change the gears unless there's something wrong with them. I already turn too many revs on the freeway as it is.

I've never really setup one of these before, and I'm wondering what I'll need as far as special tools. I have checked the pattern on gears before, when I swapped the posi on my sad little 7.5" '06 GTO differential. I didn't get into too deep, as there was no need to change the pinion bears on a 3 year old diff. Those things are easy to set up with external side adjusters, though. Just so long as they don't rust in place. Fortunately, we don't have much of that corrosion stuff in the desert.

 

If you are keeping the original gears,your work is fairly easy.You are just replacing the open carrier with a posi,so you will need an assortment of carrier shims,to reset the backlash.The pinion is not effected.When you change all the bearings,just reuse the original pinion shim.