Wondering about Posi gears

[kgl271]

Since I found my build sheet I know what gears I have. The car has 2.41 limited slip. How are these gears, are they good street gears or are they good for hauling?

[ragz442]

2.41's would be a highway gear, good for fuel economy, but not ideal for off the line acceleration.

[442MUCH]

Since I found my build sheet I know what gears I have. The car has 2.41 limited slip. How are these gears, are they good street gears or are they good for hauling?

They are good for gas mileage and driving at highway speeds. As you go higher (numerically) you get into the performance gear ratio's. With a 2:41 posi or limited slip, you can add up to a 2:73 crown and pinion.

If you want to go to a 3:08, 3:23, 3:42, etc, you'll have to change out the case or housing. Using the above gears will get you of the line quicker and into your ideal RPM for torque and HP quicker. 4:11 gears and 5:00 are for cars into racing. You can use them on a street car, but neither you nor your car will be happy.

As for hauling, I'm not too sure. The 2:41's should be OK as long as your car is set up for it (HD cooling etc.).

[kgl271]

Thanks guys, that is what I thought. The car does have the HD cooling system. So I thought this guy had the car built for towing maybe. But no sign of trailer hitch.

[GT73]

I run a 3.42 gear ratio on a 10 bolt posi rear. The rear end came from a '74 Pontiac Gran Am (not related to the N-body car) which was an 'A' body car similar to the Cutlass 'S' / 442. Bolts right in to 73-77 Olds 'A' body cars.

This in my humble opinion is the ideal gear ratio to run for the street. It allows plenty of pull for acceleration, while allowing the car not to over rev on the highway (unlike 3.73's, which rev at around 3,300 r.p.m @ 55 m.p.h.), which can cause over heating.

3.42's are an Olds stock ratio, probably explains why its the best ratio to run!

[petrofyed]

They are good for gas mileage and driving at highway speeds.

That's funny cuz i have the 2.56 in mine ('75) and my gas mileage STILL sucks! lol
about 10-11 with the 455, and that's driving it conservatively...
mine was originally used for towing because it had this massive trailer hitch welded to the frame when i bought it...had to get it torched off though in order to drop the gas tank....

[442MUCH]

That's funny cuz i have the 2.56 in mine ('75) and my gas mileage STILL sucks! lol
about 10-11 with the 455, and that's driving it conservatively...
mine was originally used for towing because it had this massive trailer hitch welded to the frame when i bought it...had to get it torched off though in order to drop the gas tank....

:eek: A stock 455 with 2:56 gears should get you about 19 MPG on the highway

[zodiacblue442]

From the trip to and from the Olds Nats which was 99.9% extended highway driving, my 442 (455 w/TH-400 and 3.23 posi.) got about 15 mpg with the a/c off and about 12.5 with the a/c on. I took the reduction in fuel economy to be cool! :cool: Cost me some extra $$$ though because I have to feed it premium unleaded.


That's funny cuz i have the 2.56 in mine ('75) and my gas mileage STILL sucks! lol
about 10-11 with the 455, and that's driving it conservatively...
mine was originally used for towing because it had this massive trailer hitch welded to the frame when i bought it...had to get it torched off though in order to drop the gas tank....

[zodiacblue442]

Kevin, as others have told you, the 2.41 is a good extended driving highway gear for better fuel economy. It was the standard ratio for 1977 Cutlass, and 1976 also if I remember correctly. My brother had a `77 442. That car had a 2.41 conventional rear end (non-posi). The mileage wasn't too good because ya had to mash the gas so much to get the car to move, especially in hilly terrain around town. He put in a rear end that was a 3.08 non-posi and it was much better in terms of around town performance. His mileage improved somewhat also.

2.41's are too high of a gear for towing anything with any weight to it. You need a lower gear like a 3.08, 3.23, or 3.42 to take advantage of the torque the engine is producing to move a heavy load. Any time a car is equipped with a tow package, the factory installs a lower gear. Hope this helps.


Since I found my build sheet I know what gears I have. The car has 2.41 limited slip. How are these gears, are they good street gears or are they good for hauling?

[kgl271]

Thanks for all the info.:D

[petrofyed]

:eek: A stock 455 with 2:56 gears should get you about 19 MPG on the highway

yeah, :eek: is right! lol
truth be told though, i haven't really taken it on a real highway jaunt yet, mainly because i really don't know the condition of the engine...it sounds good and all but it would be my luck that if i decided to take a trip from houston to dallas it would break down on me :( ....that 10-11 is pretty much my in town driving.... i have managed to put about 14K on the car since i finished it and have done nothing to the car mechanically since i got it....

[mdkingsley]

Can someone tell me if my 76 442 is the 8.5 Rear end gear or the 8.75 there are one of each on ebay and I dont know which one to bid on. I tried 442.com for the info but they didnt seem to have it.
Mitchell

[442MUCH]

Can someone tell me if my 76 442 is the 8.5 Rear end gear or the 8.75 there are one of each on ebay and I dont know which one to bid on. I tried 442.com for the info but they didnt seem to have it.
Mitchell

If it's a stock rear end then it's an 8.5" 10 bolt.

[mdkingsley]

Ken, did you change yours over or did it come 342?

[442MUCH]

Ken, did you change yours over or did it come 342?

You might be the only one who hasn't heard the story. It came with it...sorta. I bought the car off the original owner. It had 29,000 miles on it in the spring of 1979.

I was investigating the options on the car and couldn't find the option for the Dual Gate. It was July 1979 and so I called the original owner and asked.

He said that I wouldn't find the option because it wasn't offered for 1976. So I asked if he added it. He said no. He said that he went into the dealership and started to order the car.. He told the salesman (Dick Morgan) that he wanted a few extra goodies from the factory.

He had a 442 in the past and wanted one with the W30. The dealer said that there was no option for W30. He asked for the W30 manifold. He also asked for the Hurst Dual/Gate and the 3:42 rear end end.

The dealer contacted the factory and the factory said "No!" He told the original owner and he told the salesman "If they won't "Build one for me", then I won't buy a GM car". The salesman contacted the factory again and the factory basically said "Don't buy the car then". Oldsmobile was doing all they could to keepup with demand, so one car more or less didn't matter.

The original owner said Ok thanks and started to walk out. The salesman said that he could order the parts through the GM parts system and install them on the car ( at added cost). The owner agreed.

So he told me the car came with (when he picked it up) W30 manifolds, the shifter and the 3:42 ratio.

I figured it was true because I had owned the car for four months and I couldn't very well return it now even if I didn't like the idea.

In 1988 I found the salesman and he said that he remembered the car because it was the only 442 the dealership sold with a 455 and because of the extra stuff they had to do to make the sale. I asked if he had any paperwork and he said that they just sold the building in Feb (it was August) and that if he ever came across anything, he'd send it to me. I guess he never did and I heard that he died in 2005.

So, the paperwork lists that the car came with a 2:56 posi. Nothing to say 3:42. I did check it and it is a 3:42 posi. So, I suppose she's not totally original, besides, she has ported "C" heads. But I still enjoy it. The Digital tach, W27 cover and spoiler is something I added.

[zodiacblue442]

Mitchell,
8.5" rear end gear sets were in GM A-body coupes and sedans. 8.75" gears were in station wagons and El Caminos. As Ken said, your 442 will have an 8.5" gear.


Can someone tell me if my 76 442 is the 8.5 Rear end gear or the 8.75 there are one of each on ebay and I dont know which one to bid on. I tried 442.com for the info but they didnt seem to have it.
Mitchell

[mdkingsley]

Thanks for the info guys, now all I have to do is find a posi rear.
Mitchell