Does anyone here know the speedo drive gear that is used on a 3.73 with the th-350? I am switching over to a 3.73 from a 2.73 and was wondering which gear would be correct. I realize that some error would be with tire diameter, but close would be just fine.Thanks for the input...

you will have to change both the drive and driven gear for your set up and you have to know what housing you have the th350 came with two types of housing the 2 inch and the one inch housing then if you run the 2 inch housing then you have to find out if its the housing that accepts the 40-45 numbered teeth or the housing that accepts the 35-39 numbered teeth......another words is more then just changing one gear........http://www.tciauto.com/tech_info/speedo_gears.htm


heres the web site to help you out farther.....

You'll probably have to change that inner gear as Dennis says. Check this site out for more info.
http://www.73-87.com/garage/spdgears.htm

One other tip, some tailshafts have two holes for the clip to fit into for the inside gear, note which hole is used on yours, wrong hole and the gears won't mesh.

I am trying to troubleshoot a situation, but my 69 COPO clone is in Illinois with a friend........so I havent seen color of drive gear...
My question is: Do all/most G.M. factory T-400's use the same tooth drive gear???
WHAT DRIVE GEAR is most std..........

I've already run the TCI formulas etc etc

Chuck Sharin

I think it's really hit and miss, Chuck. It would depend entirely on the factory tire size and rear gearing as to what came in it originally.