shaks 442 clone

thats my 12 bolt and a gas tank from a chevelle thats also going in my cutlass




this was on the passenger side backing plate of my 12 bolt anyone know what it means?




lastly the cover it self



one more question do i have to use an impact gun to take the cover bolts off or can i take them off with a ratchet and a socket?

2blu442

Ratchet will work fine, I believe 9/16" socket. I would guess the number stamped in the backing plate is the part number. Did you pick up a U-joint for the Olds/Chev swap? They make one with two caps for the Olds size and two for the Chev size for this situation. I have a Chevelle rear end under my 1970 and it's an easy swap.

joe_padavano

Did the rear end come out of the Chevelle, or just the gas tank? That axle sure looks like a Type O that only came in 67-70 Cutlii. It may have 12 bolts on the cover, but it only has 10 bolts on an 8.5" ring gear. The Chevy 12 bolt has an upside down "V" stamped in the cover and uses 12 bolts to retain an 8.875" ring gear.

shaks 442 clone

the guy i bought the rearend off told me the tank was from like a 70's or late 60's chevelle

and that the rearend was out of a 70 cutlass sx

does anyone have an estimated cost on how much its gonna cost me to rebuild this thing?

because if its going to cost close to a thousand dollars and im only going to have a true 10 bolt on the inside i rather just do what 2blu442 did and get a chevy 12 bolt slap it in there and put some 3.08 gears in it for a reasonable cost

im in the process of cleaning it up before i paint it but like i said if its going to be expensive to rebuild i rather just sell it, by the way what do you think the rearend is worth with new fluid in it and cleaned up and painted oh and new brakes and hardware?

joe_padavano

Parts for the Type O axle are more difficult to come by and more expensive than for Chevy axles and when you're done, you still have an 8.5", 10 bolt ring gear, same as any "corporate" 10-bolt. The one big advantage of the Olds axle is that the axle shafts are retained at the outboard ends - no cheesy "C" clips here. If you snap an axle while racing, the wheel does not depart the car.

If the Type O is not currently posi, expect to pay $400 - 500 for a new posi unit. On the other hand, the asking prices for any 12 bolt housing at Spring Carlisle were astronomical...

Note I said "asking" prices, not "selling" prices.

shaks 442 clone

do you know of a place i can get a rebuild kit for the rearend that covers everything?

shaks 442 clone

also is anyone interested in buying this rear end?

joe_padavano

Here ya go:

http://www.drivetrainspecialists.com...ile/index.html

shaks 442 clone

this posi traction thing is a big investment im looking at close to a thousand dollars from start to end :/

joe_padavano

The asking prices (not to be confused with selling prices) of complete Chevy 12 bolt posi axles for an A-body at Spring Carlisle were in the $1000 - $1250 range.

shaks 442 clone

but to just buy the parts to rebuild what i have is nearly 900 dollars thats a big investment, anyone have an idea what the gears are on my 12 bolt with out popping the lid?

because if the gears inside are even a little better i might just swap the diff fluid and slap it in :?

2blu442

Look for a code stamped in the axle tube on the pass side. Should be two letters or a letter and a number. If you can find that and post it someone can let you know what the factory ratio was in the rear. There's always the chance that it may have been changed over the years, but being a non-posi hopefully that hasn't happened. Are you going to race the car or use it as a daily driver? I've heard a lot of good things about the corporate 8.5 rear ends and the parts are plentiful for them. John

shaks 442 clone

making it a cruiser out where i live all the cool kids have old skool cars

but i have one advantage, a grade A mechanic who helps me a lot

GoldOlds

I'm grateful this topic has come up, since I'm a bit confused about the rear end in my own car ('69 Cutlass). The guy I bought it from said it's an OLDS 12 bolt, but the car was Canadian built, which I was led to believe means it has a Chevy rear end. I'll look for the upside down V someone mentioned earlier. Isn't the type O an 8.3", not an 8.5"? I'm not trying to split hairs, I just want to know if there's an internal difference (at least in strength) between the Chevy 8.5" 10 bolt and the type O 12 bolt. I can live with the strength of the 8.5" rear, but anything that's only marginally better than the 8.2" probably won't cut it. THIS site describes the Chev 12 bolt cover as scalloped, which I believe refers to the bulge not present on the surface of the Olds 12 bolt cover. If that's the case, it looks like shaks has the Chev version.... right?

- GoldOlds

88 coupe

This is a Chev 12 bolt cover.



Norm

GoldOlds

Thanks 88, that's a good, clear pic. It's gonna take some crawling around to figure it out on my car; the gas tank covers the top half. Do ALL Chev 12 bolt covers look like that? I had one on the '72 Chevelle I sold a few months ago, and I don't remember the big upside down V, or the lines that run between most of the bolts (although my memory's pretty bad). It had the same vertical bulge, though.

- GoldOlds

joe_padavano

Yes, all Chevy 12 bolt covers have the "V". Pretty much every GM rear axle has the vertical bulge for clearance to the ring gear.

GoldOlds

Well, sometimes it's good to be wrong. My Cutlass does in fact have the "Type C" rear end. Before that pic was posted, I thought the upside down V would be some tiny little notch buried under grease and dirt. Once I crawled up to where I could see the top half of the cover, it was as clear as day; it looks EXACTLY like that pic.

- GoldOlds