I went from 4:11 to 3:25 gears on my Shoebox with a 3 speed 1:1 final drive ratio trans. It still revs a little higher than I want at cruisin speed so my question is I have 15" tires that are 65 series low profile radials that I picked up until I can afford some 75 series wide whites radials. Any thoughts on what a taller tire will do to my RPMs? Think it will be a noticable difference? Thanks for any thoughts.