Well i just bought a rear disk rear end out of a 88 iroc. it has a 3.45 borg warner gear ratio. it came out of a manual car, and I have a 700r4. I need to know what speedo gear i need, like the color and the # of teeth... i went to this site

http://tciauto.com/tech_info/speedo_gears.htm

but did not understand it.... thanks in advance

 

I have both gears that I pulled out of my 700R4 with 3.42 rear. They are a gray drive 15 teeth, and yellow 41 teeth.

For a cable driven speedo you need:
GRAY 8642620
YELLOW 1362195

For a VSS you need:
YELLOW 25513048
same gray one

BTW; I have both gears and the VSS(electronic) to go with it if you are interested PM me.