I'm not preaching from a soapbox (but this forum does seriously frown on illegal street activities) and I won't deny I've driven recklessly and raced in the past and I'm lucky that I never got caught or killed myself or someone else. I don't know all the facts, but as I stated before, the only reason for a speedo is to obay posted speed limits, it serves no purpose in a real motorsports competition. The reason your speedo reads to the speed it does is becuase the car is legally allowed to drive those speeds in other parts of the world, but only in places where the road conditions and other factors meet certain standards. I don't think I'm jumping on you for what you posted or being unreasonable, and I would never lock a thread just because I don't agree with someone, I'm just telling you that what your doing is dangerous. Regardless of the motor and modifications, driving an 18 year old 4 cylinder economy car at over 140 mph is just plain dangerous and you could potentially kill yourself or someone else. A tire blowout, a mechanical failure or a simply a bad change in road conditions (puddle, gravel, dirt, oil) are going to be much harder to compenstate or recover from at those speeds.

As for your question, most people say OE speedo's don't read accurately after 100 mph, but I've heard an explanation why. I guess the tranny could accellerate beyond a speed the sensor can reliably read but that seems unlikely. I don't believe you can simply swap a sensor and cable into your tranny from another car and have it work without issues but your cable drive unit should control any Honda cable driven dash (specificaly I thinking older 1st or 2nd gen Integra's). Honestly though, I can't think of any real reason to have a speedo that reads beyond 100 mph though.