Speedometer calibration
 

I posted this on the tranny board, but I was hoping someone here may have some insight also.

I just did a gear swap in my firebird, from 2.73 to 3.42.

What exactly do I need to do to make the speedo read correctly?
It's the electric one, not cable driven.

Do I need to change the gears in the tranny, or do I need to change something in the speedo itself?

The car is an 89 formula 350, the wheels and tires are stock sizes, and the tranny is a stock 700r4.

I've asked several mechanics and all I get is a lot of head scratching and dumb looks

I also searched the archives, and there is so much information in there I started to get confused.


Thanks for any help
John

I used a Dakota digital box. It works great. You can change the gears in the tranny but that really sucks.

All you need to do is change the gears in the tail housing of the trans. It can be a pain because of a little clip you have to watch out for though. Go here for directions: http://www.sethirdgen.org/vss.htm

I am not sure on the correct gears you need though. The dealer can help you with that.

If you don't have a 32mm wrench.. buy one!! I broke the drive gear using other methods to install it.

Thanks, thats the information I needed, I ordered the parts today from the chevy dealer.



John

No problem :cool:

Update: The gears didn't fit, the new driven gear is a 1/4" larger than the old one, I need to change out the sleeve as well.

Whatever gets you 2,000 pulses per mile will get your speedo just about perfectly calibrated (well, 2,002 actually).