Pete76Shark

I had a 3.55 diff install months ago with no problems. Spedo reads 6 mph faster then it should. I pull the spedo drive gear and retainer out of my TH350 and it is red with 21 teeth.

Zip says the 21 teeth gear is for a manual tranny but that must be a mis-print.

I know I want to go to a 25 tooth orange gear but my question is do I need a new retainer or can I use the old one ?

Zip does not even offer a retainer for a 25 tooth gear.. This is strange
:banghead:

KJL

Sorry I can't answer your question but I am planning on doing the same thing with my car. I am running a Turbo400. Did you go from a 3.08 to a 3.55? Do you feel a difference? Some tell me to go with a 3.70 but that seems to extreem for me.


[Modified by KJL, 9:25 AM 9/9/2003]

Pete76Shark

Yes I went from a 3.08 to a 3.55 and the difference off the line is very noticable. Also at 80mph I run at 3500 rpm which I am ok with. The guy that did mine suggested the 3.55 and I am happy with it.

The speedo gear thing is a pain in the rear.

I am working with Corvette Central now to try and figure out what gear I need. they say adding one gear will slow the speedomete down by 5mph. ZIP says adding one gear will slow it down by 1.5mph but that seems wrong to me.

Anyway I am sure that my speedo is reading 6mph to fast so I am going to add one tooth and go with the 22 tooth gear. Just need to know from Corvette Central if I can use the sleeve I have or if I need a new one, I suspect the one I have will work.

criz51

This site has a breakdown of gears/ratios
http://www.novaresource.org/speedo.htm