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Just rescued an original 68 442 that came factory with the 300hp 2 barrel, turbo 400, with a 12 bolt open 243 rear end.......21,000 orig miles in near mint condition. QUESTION.....I can live with the 2 barrel and automatic but CAN I TURN THE OPEN REAREND INTO A POSI WITHOUT ANY MAJOR ALTERATIONS
Just rescued an original 68 442 that came factory with the 300hp 2 barrel, turbo 400, with a 12 bolt open 243 rear end.......21,000 orig miles in near mint condition. QUESTION.....I can live with the 2 barrel and automatic but CAN I TURN THE OPEN REAREND INTO A POSI WITHOUT ANY MAJOR ALTERATIONS
Welcome.
Your car actually has the L65 400 2bbl motor. 9.0:1 CR, 290 HP. The standard rear with this motor was the 2.56. There was no 2.43 offered. Unless this car was built in Canada, that's also not a "12 bolt" axle, despite the number of bolts on the cover. It's a Type O axle that is unique to the 1966-1970 Cutlass models. The 8.5" ring gear is held to the carrier with ten bolts. All parts are unique to this axle. Posi carriers were factory available but are difficult to find. Aftermarket posi units are nearly nonexistent. No internal parts from a Chevy 12 bolt interchange, nor do parts from the 8.5" ten bolt.
If this IS a Canadian built car, it will have a real Chevy 12 bolt axle, and parts are readily available.
Joe I was going off the 2.43 stamped on the big gear in the rear end not sure exactly how to tell what the rear end is other than the ol spin the tire and watch the drive shaft
My car did come and still has factory dual exhaust? Was it supposed to come with a single exhaust? I have checked all numbers and everything matches the protecto plate still in the glove box from the original owner
Joe I was going off the 2.43 stamped on the big gear in the rear end not sure exactly how to tell what the rear end is other than the ol spin the tire and watch the drive shaft
Look at the numbers stamped into the edge of the ring gear. A 2.56 ratio will have 41 A 16 (41 divided by 16 = 2.56).
Below is some O-Type info that Brian Trick posted many years ago. You would need a 673 carrier to go with your 2.56 gears.
O-Type 12 Bolt
Here is a list of the posi units & what gears they will fit:
#673 = 2.56 & 2.78 ratios, 28 spline
#671 = 3.08 & 3.23 ratios, 28 spline
#588 = 3.42 & anything numerically higher, 28 spline
#672 = 3.42 & anything numerically higher, 31 spline
Last edited by Fun71; October 16th, 2017 at 12:33 PM.
My car did come and still has factory dual exhaust? Was it supposed to come with a single exhaust? I have checked all numbers and everything matches the protecto plate still in the glove box from the original owner
That's a good catch. The chart that I posted above has a typo that I've not noticed before, as it shows single exhaust for all the 400 motors except the W-30. This is not correct. All the 442 installations got dual exhaust and the cutout back bumper. I suspect the L65 and L78 installations in the VC were single exhaust.
I'm toying with the idea of installing a powertrax unit in my rear end to make it a posi. To my understanding you just remove the spider gears and drop it in. https://www.powertrax.com/traction-s...utlass+holiday
Yes thats what caught my eye Mine does have dual exhaust as the factory exhaust is still on it. Could they have put a bigger engine in but topped it off with a 2 barrel carb?
Its intent was a highway cruiser with "some" economy, (lower compression, 2 barrel, highway gears) not a boulevard bruiser. Premium gas was not required as was with the 10.5:1 compression 325HP and up 400cid, 442s. Turn Pike cars are kind of uncommon. This does not mean more valuable. Its a basic 442 meant for long-haul highway travel. It should have the TH400 transmission in it. Whats the interior look like buckets with console or bench? Pictures are highly recommended here.
Yes thats what caught my eye Mine does have dual exhaust as the factory exhaust is still on it. Could they have put a bigger engine in but topped it off with a 2 barrel carb?
I don't know what you mean by a "bigger" engine. It's a G-block 400, period. The L65 was the low compression 2bbl motor with dished pistons. The others had flattop pistons and high compression. A borescope in the spark plug hole will show you which pistons you have. The cams were different also.
Contrary to what people want to believe, the factory did not randomly swap parts on the assembly line. Every change was documented with factory engineering and dealer bulletins. Every one of these cars built had to be backed by a warranty, so the dealers needed to know how to fix them, which means they needed to know the configuration and appropriate parts. People who claim "anything was possible" are sellers trying to get inflated dollars for a "one of none" car.
Thank you I believe you have the knowledge I was looking for and I will check with a bore scope but I am sure this is a factory car. Any other place to look for a build sheet other than under back seat or on top of gas tank?? I pulled the back seat and found an inspection sheet that actually confirmed the trailer / tow lights that are tied into the harness in the trunk are from the factory and not just an add on from the orig owner but no build sheet. This is my find
. As pointed out by others, it is a 442 with the Turn Pike package, with 9:1 compression 290 hp, 440 Ft Lbs. of torque. My buddy has one. He has added an intake with a four barrel over the years, and a complete 3:23 rear end.
Last edited by 1969w3155; October 17th, 2017 at 09:59 AM.
Any other place to look for a build sheet other than under back seat or on top of gas tank??
You can stop looking. Your car was built at Lansing, and that plant was famous for NOT including the build sheet in the car. Build sheets were never meant to be part of what the purchaser received when he bought a new car. They're just artifacts of the production process that might or might not have been left in the car, and, if they were, could have been left in any number of places. It's not worth tearing a car apart to find it. Most people who do find one find it in the process of taking the car partially apart for other reasons (such as to replace the carpet or gas tank or repair a window regular as some have been found inside doors).
But, as I say, in your case, the point is moot as Lansing was more meticulous about this than other plants and did not leave them in the car.
Still has original battery cables and radiator hoses and since I see your car in the picture question to you a Vista Cruiser was the station wagon correct?
I believe with your advise that mine would have a 2.78 open rear end but I surely would like it not to be a peg leg any ideas on turning it into a posi
I believe with your advise that mine would have a 2.78 open rear end but I surely would like it not to be a peg leg any ideas on turning it into a posi
Yep, 39/14 = 2.78
As for converting it, see Post #2. Your only option is to find a used posi unit for a Type O. Alternately, you can replace the entire axle housing with a different one, like a 71-72 Corporate 10-bolt.
I'm fairly certain that either Brian Trick or Monzazz posted that the 8.5" 10 bolt version of the PowerTrax Lock-Rite locker works in the O Type differential.
Not that I am advocating an automatic lunchbox locker for a street driven car; just relaying info that was posted.
Last edited by Fun71; October 18th, 2017 at 02:30 PM.
I'm fairly certain that either Brian Trick or Monzazz posted that the 8.5" 10 bolt version of the PowerTrax Lock-Rite locker works in the O Type differential.
Not that I am advocating an automatic lunchbox locker for a street driven car; just relaying info that was posted.
I'd be interested in hearing from anyone with firsthand experience with one of these in a street car (as opposed to a drag car, Jeep, or other offroader). Everything I've seen online seems to point towards noisy and jerky performance in turns, which I would expect from the straight teeth in the unit. That probably doesn't matter in a truck or Jeep, but one might care in a more civilized car. This isn't a clutch-type anti-spin with friction plates that progressively slip on turns. It's a machined locker unit with straight-cut dog teeth that engage and disengage.
I'm toying with the idea of installing a powertrax unit in my rear end to make it a posi. To my understanding you just remove the spider gears and drop it in. https://www.powertrax.com/traction-s...utlass+holiday
I posted this way up in Post #11. I have a few friends that are running the powertrax with no issues on the street and no strange noises.
Found this site in an old post, I guess all they do is Cutlass and 442
They carry a replacement but would need to turn it in to a 3.42 gear from talking with them. Anybody know or dealt with this company?
I'd be interested in hearing from anyone with firsthand experience with one of these in a street car (as opposed to a drag car, Jeep, or other offroader). Everything I've seen online seems to point towards noisy and jerky performance in turns, which I would expect from the straight teeth in the unit. That probably doesn't matter in a truck or Jeep, but one might care in a more civilized car. This isn't a clutch-type anti-spin with friction plates that progressively slip on turns. It's a machined locker unit with straight-cut dog teeth that engage and disengage.
I have one in my Jeep, but it's in the front diff so it gets used only when off-road in 4WD. I have heard the same things on the 4WD forums about driveability issues with them in the rear. The diff locks any time you're on the throttle, so folks advise to coast around corners and turns.
Found this site in an old post, I guess all they do is Cutlass and 442
They carry a replacement but would need to turn it in to a 3.42 gear from talking with them.Anybody know or dealt with this company?
Those are modified Ford 8.8" carriers. Brian Trick and Monzazz have experience with them and have posted about them quite a bit over the years.
The link you posted says the carrier for 2.56-2.78 gears is a special order item. Interesting that the person you spoke with said you would need to swap gears and use the 3.42 series carrier and not mention the special order carrier for 2.56-2.78 ratios.
I have used the Powertrax and No slip before. In my 78 1/2 ton and the 7.5 in my 88 Cutlass. They do make some noise but do provide traction. I broke the pins off in the 7.5, using slicks and it locked at all times. Talk about a violent experience parking!
October 16th, 2017, 08:52 AM
12 Bolt Open to Posi?
