speedo gear help

I am about to order a new speedometer gear but not sure which one I need. I looked at year one's chart.

http://www.yearone.com/pco/A_0308/full.asp?page=246

I just got a 3.21 ring and pinion installed and according to the chart I would need a 32 tooth gear. My current tire size is P215/70/R14. However next spring I plan on getting new tires and I would like to go bigger. I want tires that are wider and a tad bigger in diameter. A P225 or P235 seems like it would make a more visual impact. Right now I have 14 inch ralleys but not sure what the biggest tires are that will fit on them. The year one chart has a P225 but for a 15inch wheel. So my question is what gear should I get for a 14inch wheel but wider than 215? Or is there much of a difference in the speedometer reading between a 14 and 15inch wheel. Any information is appreciated. Thanks

On another note what is everyones opinion for the best tire combo for a '74 duster with 14inch ralleys?

Thanks
Author: admin