My friend here has a 91 RS 305 auto. Well I was lucky enough to pick up a set of 3.42 gears with the locking rear from a 96 Camaro. I can install the gears, thats not a big problem, my problem is, how do I fix the speedometer, because won't it be off by alot because of going from 2.73 to a 3.42 rear end. How do you fix it?
Thanks,

 

you can set up a ring and pinion but not a speedo, damn. change the driven gear on the speedo

 

You need a 45 tooth driven gear and a sleeve to match it. Look up my posts on this forum for all the info because I just did the same thing a month ago.

 

Thats cold.

 

It really depends on tire size. What size are the tires that are on the car now? Some people can get away with just changing the drive gear or driven gear. You may or may not need both. www.700r4.com/ has a calculator thats easy to use and if you do a quick search on this board you can find all the GM part numbers under one of my old threads about 8 months back.

 

The car has 245/50/16's on it, I went to that site,(thank you by the way) and i used their calculator, It came up saying to use a 15tooth drive gear and a 40 tooth driven gear.
Now my next question, where do you put these gears at? and how bad are they to install. I have done a few rear ends, that Is how I know what to do. But I never cared about the speedo being right Since its not my car, he cares. I was hoping since it is a 91 that it was something that was just programmed or you had to burn a chip for. O well.

 

Repalcing the speedo gears is easy. The driven gear is connected directly to the VSS sensor or speedo cable on your transmission. Just unbolt and it pops right off.

On an auto tranny, unbolt and remove the tranny tailshaft and you will see the drive gear. I think there is still a tech article that shows this. Just be careful not to snap the retaining ring that keeps the drive gear in place.

Your wheel/tire combo is stock for that year (z28 option). Just go to a GM parts desk and tell them you want the 3.42 drive/driven gear set for a 91 Camaro. If the rep gets confused, tell him/her to cross reference it off of the V-6 model and you should be able to get both gears for under $25.

Electronic speedo cals didn't appear until the 4th gens were produced. Hope this helps.