I currently have a 1971 TH350 transmission with factory green 9 teeth drive gear and orange 35 teeth driven gear. Changed the tires to P235-60 R 15 and the rear axle gears to a 3.23.
Through searches on this site I need to change my driven gear to a gray 22 teeth for my speedometer to be at least close to the correct speed. I have a speedometer housing for 35 to 39 teeth and I know there is one for 40 to 45 teeth is there one for the 22 teeth or do I use the 35 to 39? Any help greatly appreciated.
Thanks Lewis

 

You need to change the drive gear. Get an 18 tooth gear for a 700R4 (same size as for a TH350) and a 45 tooth driven gear and you should be about as close as you're going to get.

 

Thank you for your reply. I was hoping it would be a fast and easy fix but I guess I will be installing a new 18 tooth drive gear! again thank you for the information and reply.

 

PATC - they have fairly quick service and can hook you up. They're in Louisiana. https://transmissioncenter.net/shop/...er-drive-gear/

I used them for my drive gear changing out my TH350 to 3.42:1. Good pricing. They have a toll free number if you need to talk.

 

Thank you Allan I appreciate the link.

 

How did that work out Allen?

 

Just fine Randy, They're a great company to do business with. I ordered the Drive gear and tailshaft reseal kit from them. I already had the driven 39 tooth. The adapter I had in the car fits the 39 tooth. It was stubborn to get out. One thing to note: if replacing the driven gear, always a good thing to replace the adapter O ring.

 

I'm glad that fixed your calibration issue and that I could help.