A friend of mine needed a tune up an his ford. He got the parts and I did the work, It took me about 1 hour, Traded for a 12 bolt out of a 1970 Olds 442. He said the reason he removed it was that it did not have good top end speed on the Highway, Looks good, It looks to have a 3:73 Gear by turning the Axle and watching the Pinyon. I need to take the time to check it out closer { Pull the cover }. Does not seem to be a possie. Axles turn opposite while turning 1 axle. I'de think from the car { 1970, 442 } with the Gear it would be ? Factory option, rebuilt or from another car ? ANY IDEAS?
It'll be interesting to know what you find when you pull the cover. If I remember, pulling the 12 bolt cover off will reveal 10 bolts retaining the ring gear...surprise. Here's some more I dug up: Devon
Won't be 3.73 in a "type O" Olds 10 bolt rear. This style r/e's ratio will jump from 3.42 to 3.91. Your probably off on the ratio, as trying to count as you spin the pegleg rear. Easier to just pull the rear cover & look for ratio ID engraved on the side of ring gear or count the teeth on the ring & pinion & divide.. Before pulling the rear cover, does it have a large inverted V shape on it? If so, it's a 12 bolt with c-clip axles. If the rear cover is smooth & has 12 bolts, it's a "type O" which is by far the most common style rear that came in '67-70 Olds Cutlass & 442's. These traditionally have little value in peg leg high ratio form & I usually part them out & cut the outer coil spring perchs off for later use. While modified new Ford 8.8 posi carriers & Richmond gears are sold to fit the type O's, they aren't cheap. When built to the hilt, the "type O" is not near as strong as when same $$$ is put in a '71-72 8.5 A-body rear. Weakness wise, I'd be hard pressed to say the axle is the weakness of the typical type "O". Like most 8.2's, the main weakness is a lack of pinion support. Olds addressed axle strength issues in '68 with a few models receiving 31 spline axles, but these required a specific axle housing & were no longer used by the '70 model. Finding & replacing stock axles for '70 model Cutlass-442-Vista Cruiser "type O" rears is often no fun, as many different axle versions were made. In parting A-bodys & building rears, I've pulled both 28 spline sealed ball bearing (RW507CR) & tapered bearing (A9) axles from '70 type O's, along with a 28 spline version that takes larger diam axle bearing (used in Vista & flattop wgns). Hope this helps. Got Posi? :3gears: Roger
There will be a code stamped into the axle tube to the right of the cover. Limited slip codes are as follows for 1970 R3 - 2:56 SB - 2:78 SD - 3:08 SF - 3:23 SH - 3:42 SJ - 3:91 W30 & W31 TM - 3:42 TO - 3:91 W27 SV - 3:23 SX - 3:42 SZ - 3:91
Devon, are you saying a corporate 10 bolt out of my GS is stronger than the 12 bolt rear end I pulled from a 70 Olds 442?
I have used the 12 Bolt OLDS rear end in my cars for years and they are very strong ( more than any chev corp rear ) it also has bolt in axels and is safer at the track. The current olds rear end in my 64 post car has run 12's and was in my rag top for years under heavy abuse I would take any and all 12 bolt OLDS rear end parts if you are just going to part them out. :TU: after all with 12 Skylarks/gs cars i can use all i can get I prefer the Olds rear end over the chev style any day but parts are getting impossable to find ( with so many heartless guys just cutting them up :eek2: ) Ken
Checked it out. OK, Checked it out today, . Looks like the Olds 12 bolt to me. there is still a difference from a 10 bolt to it, the tubes and the housing are larger, also looks like the Axle diameter. They are bolt in Axles. Removed the cover and was disapointed to see that it was not a possie. Then I noticed the narrow ring gead and the lard pinyon, I new right away that the ratio would only be good for the highway. 16 pinyon teeth and 41 ring gear teeth, if I counted right. 2:56 if I did the math right. Everything looked great though . no visible wear on the teeth face, or corosion - rust, ect. Saw the numbers on the ring gear but did not have my glasses on. Think Ill stay with the 10 bolt I built, A possie with 3:73 Richmond Gears. see Pic below. I plan on converting fron the turbo 400 trans. to the 200 4R. This should give me the best of both worlds. Ill hold on to the Olds though, considering in south Mississippi {Biloxi} All the salvege yards are crush happy. Old cars are hard to find. I buy up what ever I come across that is of value. Ill try to post some pics. tomorrow on Junk Yard Jewels that Ive picked up over the last few years. Thanks for all the replys. :TU:
Ken, I'm far from heartless, just realistic. Have personally saved several '68 31 spline 3.42 & 3.91 factory anti-spin rears from further rigged abuse. On one I pulled out of a '70 Chevelle SS clone, I spent close to 8 hours just removing some form of welded on "traction" devices. Ton of careful grinding after the plasma cutter just to get the hsg tubes clean w/o gouging. Had to order new axles, as well, for that one. Also have recovered, rebuilt, & sold quite a '69 & 70 3.42 & 3.23 factory anti-spin rears. Most ended back up in restored 442's & Cutlasses or are awaiting their turn. Have also assembled quite a few type "O" rears that have since been run into the low 12's & high 11 sec 1/4 mile range. Am sure there are Olds guys out there that have run even quicker on them, but there is a limit & it's in the design of the pinion area of the center housing. Just like in most 8.2's, the problem with the "type O" r/e is to go a LOT quicker, there is a lack of pinion support in the stock "type O" housing. Combine that integral problem along with what we would both agree are expensive & hard to find performance parts (anti-spins, good ratio gears, 31 spline axles), not good. Both are disadvantages when compared to what can be done with an 8.5 A-body or a 12 bolt... both of which myself & quite a few others have taken in HD posi form into the low 10's & high 9's in 3600lb A-bodys. While I'm big on tapered bearing bolt-in axles, bolt-in axles, in theirself are not the major strength positive you make it seem. While stock c-clip axles are inferior, sealed bearing axles bearings are also inferior, & why GM & Ford went to the tapered bearing design. When one starts comparing apples to apples, I just find it hard to upgrade the "type O" singletrack rears. Just too easy to spend $1500 on building up a pegleg 28 spline "type O" into a posi with new gears & axles, & the strength afforded will be nowhere near that of same $1500 put into a '71-72 8.5 A-body or any true 12 bolt. Got Posi? :3gears: Roger
Freazoid, you have the most common version of the '71-72 8.5 A-body rearend. Same exact axle tube diameter as the type "O" rear, or a real 12 bolt rearend for that matter. On it's longer pinion, it uses exact same pinion bearings as a 12 bolt Chevy car rear. Also came stock with tapered bearing axle bearings. No reason to get caught up in the 12 bolt hype, the 8.5 A-body rear you have is very strong & very upgradeable. In blueprinted stock "S" spring posi form, I have longtime friends who have run as quick as mid 1.50 60 foot times in 3600-3800 lb A-bodys. At that range, I personally like to use aftermarket axles, but can't convince everyone that at that point they're on borrowed time with stockers p Got Posi? :3gears: Roger
Thanks Thanks, Like said I built the 10 bolt myself. I spent around $500.00 Bearings, Seals, Gears and a good used possie.{$50.00} For Possie from a friend. OH yea ,Shim Kit. Took several trys with the shim kit for the desired Gear pattern, Brg. load and back lash. Its been 4 years and not a problem. I need to go to the Track and see what my rod will run. Yea also real pleased with this post Alot of helpful info for all.
