Available stock gears

[Cole]

OK, so I know everyone asks about gears. I've read through most of the other posts. What I'm interested in knowing is which gear/trans/engine combos came in which models in which years. The reason is that I'm going to be shopping for another g body to build up for a nice daily driver. So what I'm looking for is a SBC, 2004r and gears between 2.29 and 2.73. From what I understand, the following cars would come with that:

84-88 monte carlo (non SS)
84-88 cutlass supreme (not 442 or hurst olds)
84-87 grand prix
84-87 buick regal (not t-type, GN etc)

Although I'm not sure about the Olds cars. Does anyone know for sure if they ever came with 305's? Or were they all 307's and v6's

Also, does anyone know an easy way to tell what gears a car might have just from looking at it? Were certain ratios more common for certain models/years? It seems to me like the buicks might have been geared higher as they were targeted for older people. Not sure though.

Before everyone starts telling me, I know I'll get virtually no performance from such a setup. I'm more concerned with having a nice driving, nice looking car that is easy on gas and simple to maintain and repair.

Any input is appreciated

Cole

 

[clean8485]

There were quite a few early '80s Olds Cutlass models that came from the factory with 305 Chev engines. I know that the 442s & Hurst cars had the 307, but many other Cutlasses had the 305. I know that the '86 GP 2+2s had a 3.08 rear gear with posi, but those cars are rare. Other than the other performance models, I'm not sure how to tell the rear gears by looking at the car. If you have the VIN of a particular car, and know how to decode RPO codes, you may be able to figure out the rear gear ratio. Sorry I can't help more than that.

 

[Cole]

I've tried decoding VINs before. The information isn't particularly useful. Just tells the vehicle type, year, engine, production plant etc.

Thanks for the Cutlass info though. I read somewhere once that they only came with olds v8s. Good to know they are another option.

 

[clean8485]

If you can find what is called a service parts ID label on the car (usually found on the underside of the trunk lid), it has the RPO codes for that vehicle. The rear axle codes are usually listed starting with a G letter designation. The list of RPO codes can sometimes be obtained by getting a GM dealer to use the VIN for the vehicle to get the list of RPO codes. That depends on the year of the vehicle though, as the dealer can only go back so many years with that type of search. Finding the ID label on the car is usually a better choice, if you can.

 

[andrewmp6]

id go for a 3.55 or 3.73 both are great highway gears with a overdrive transmission

 

[Cole]

OK, yes, I know the codes you are speaking of. They are 3 digits for the gears right? I have a list somewhere. I didn't know you could look them up based on VIN. Good to know. Thanks.

As for 3.73 gears, they would be terrible on the highway. I'd be revving over 2000 RPM at 62 miles with .67 overdrive. I might aswell be running a 4 cylinder with gears like that. Sure, they'll feel great when I mash the throttle, but they'll waste a rediculous amount of gas.

From a mathematical standpoint, you only need about 50 lbs per HP to keep a car going on the highway. At 2000 RPM, I would be wasting almost 25 HP. That's a lot of gas. 2.73 gears would put me at 1500 RPM. Much more reasonable. If I need to accelerate fast, downshifting isn't hard.

Remember, this is for a daily driver with no performance aspirations. I will not EVER be trying to race it. If some idiot in a rice rocket wants to fly by me and get a speeding ticket, I will just laugh and enjoy the rest of my drive. I believe in keeping racing at the drag strip, and this car will never see one.

 

[andrewmp6]

if you care about mpg that much get a geo metro or prius. a g body isnt litte or light 20 to 25mpg would be the best it could ever get maybe with a v6. the 2.73 would take off from a stop like a semi going up hill.

 

[srercrcr]

Best I remember the axle code is stamped in the passenger side of the axle tube, front side....a real bear to read, may need chalk.
Get back with the code and somebody can decipher it.

 

[pontiacgp]

when your calculating the gearing don't overlook the size of the tire as well. I think the stock wheel was 215-65-14 and there's not many of us still running that size and the tire size affects the gear ratio. I'm running 255 60 15 in the rear and my speedo is off close to 20%. The 241 gears in my diff with those tires work out to probably under a 215 gear ratio. I don't have the formula to calculate but if someone does I appreciate if you'd post it.

and here's a link to the diff codes

http://www.g-body.org/tnt/diffs/diff-codes.php