OK, I have used the chart on the Nova resource web site and call me an idiot it doesn't make sense to me so I need help. I am installing my new 12 bolt with 3.73 gears. My tires are 28.0 " in diameter. I am running a TH350 transmission in my 69 Chevelle. The chart doesn't make sense at telling me what I need,the gears listed do not match the chart. Please help!! Thanks

Just counted what I currently have. White "drive" gear @ 8 T. Blue "driven" gear @ 20T.

Try the team chevelle chart. I calculated the ratio for you at 13t drive gear and 35t driven gear, or 16t drive gear and 43t driven gear. Those numbers were for large gear speedos. These are for small gear: 9t drive and 24t driven or 7t drive and 19t driven. Like i said if the chart is wrong then i am wrong. Hope this helps.:waving:

What is meant by large gear or small gear speedos. I guess I need a quick lesson. Thanks

7 Tooth Pink
19 tooth Natural

Don't know what the part numbers are. Seeing that dealerships are closed on sundays.
Your looking around 20 bucks.

Small gears fit in 1 inch speedo housings that go into the tail housing of your trans. Large gears fit in th 400 trans (large housings). I posted both choices because of limited information while searching at the previous post. I have have since verified the correct selection in the post afterwards. Happy hunting.

OK, I have used the chart on the Nova resource web site and call me an idiot it doesn't make sense to me so I need help. I am installing my new 12 bolt with 3.73 gears. My tires are 28.0 " in diameter. I am running a TH350 transmission in my 69 Chevelle. The chart doesn't make sense at telling me what I need,the gears listed do not match the chart. Please help!! Thanks

Just counted what I currently have. White "drive" gear @ 8 T. Blue "driven" gear @ 20T.

3.73/28.0"/TH350/8T drive gear = 21.471 driven (Red 21T)). There may not be a 21 tooth available so maybe a 22T or change drive gear to get a closer combo. Are you sure your drive is white, according to the chart an 8T drive should be orange.

http://www.tciauto.com/Products/TechInfo/speedo_gears.asp

I should say it's the "normal plastic color"? But I had my big ol head up to it today and it does have 8T. Do you think the 22T is going to be close enough? Or would you recomend switching everything?

Check around for the 21T, it might be available. Raptor-Transmissions has one listed on their web site and they probably aren't the only ones. Don't forget to check the tooth range on your bullet.

http://www.transmissioncenter.net/speedometer_calibration_______va.htm#350