so i have been debating this for a very long time. this is not my street rode and is in fact my daily driver which does see highway use. now i know its a 2000 mustang with 3.27 gears and it cant seem to get out of its own way. well for me anyway as i have a 5 speed galaxie with 4.11. anyway i have bigger tires on the rear that seem to pull me along in 5th gear at 2000 to 2100 rpm at 75ish mph. needless to say this is too tall would like to stay below 2500 at resonable speeds in 5th(75mph or lower) imlooking for what would give me a solid 2000 to 2100 around 65 to 68 and around 70 to 72 a solid 2300 and preferably no higher. rims are the 2005 mag style rims with tires slightly bigger than the stock pirellis. thanks want to get this figured out so i can get going. used to know the math equation but have since forgot it. if someone would know that id take that too. thanks again.