where would i find the ratio for the speedo in my car? the current speedometer is shot, and has blessed me with a ticket i definitely didn't need. due to the year of my car (85) the speedo is only rated to 85 and i would like to go with a 110 or 140.

problem is that they are very expensive, and difficult to find. its cheaper to go aftermarket, which brings me to my question. if i get an aftermarket speedo, will it simply swap in? (other than the obvious dash mods) or will i need to obtain an adaptor? is the factory speedometer 1:1?

and to reply to the obvious questions, the gears are all factory, it has the proper gear in the tranny, and the cable is good. the problem with the unit is it is fairly accurate when i first start driving, but rapidly gets more and more innacurate. i had my cruize set at 72 in a 65 zone and the cop clocked me at 81, and also paced me. my tires are smaller than stock (winters) so it should have been exactly the opposite. not cool

thanks everyone!