John 89 Formula

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

dd85T/A

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

Omega

iTrader: (1)

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.

John 89 Formula

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



John

Omega

iTrader: (1)

No problem

John 89 Formula

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.

Vader

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