speed gear?

[buick83-T]

HI,

My speedometer is off 11 mph. I have a 26 inch tall tire and stock 3.42 gears currently. I plan on upgrading to 3.73 gears soon. This is on a 83' T-type with 200-4r trans. What speedometer gear should I use for 26 inch tall tire and the 3.73s to get correct reading?
Thanks

 

[MeanBuicks]

You'll also need to know what drive gear you have on your governor. Here is a page to help you out with your calculations: www.tciauto.com/tech_info/speedo_gears.htm

 

[Scott King]

3.73 X 20.2 = 75.346 divided by 26" = 2.897 so using gears available for the 2004R a 10 tooth drive gear and a 29 tooth driven should be close.