ok, installed new speedo, and it is off. i can physically re-calibrate it by moving the needle past its stoping point. the needle will then move on its spindle and a new stoping point is set. so far i have done the ol' this feels like twenty five ::move needle to 25: calibration, not very acurate, i was wondering, where do your needles stop on 140mph speedos. and no i don't mean where do they rest, it will always rest straight down, but the needles range of movement is way different. without having you all actually come to my house and show you i don't know how i can better explain this. if you can help please do.

 

I have the same woes... I had a 115 and I went to a 140 speedo, plus my car came with 15" rims and I put 16"s on... the faster I go, the more it's off! 40 is really 60!

 

Putting in a different speedometer won't effect the acuracy of it. The two plastic gears in your transmission do that. If you change your overall rear tire height, not the rim size then it will be off, also if you change rear end gears it will be off.

But i'm not sure how to calibrate a speedometer once the needle has been removed.

 

There are shops that can calibrate the speedo, but around here it's about $100