If I go with 4.10's in the rear...?

[LT19C1]

How do I recalibrate the speedo so that it reads accurately again? I remember back years ago when I owned a Mustang it was just changing a little speedo gear in the tranny tailstock on the end of the speedo cable. But I don't think the z's have a speedo cable...so how?

[mattinator1973]

I have heard for 93's you can do it by changing the speedo gear or something like that in the tranny. If it is a 94+ you can either do it from the tranny or do it by reprogramming your pcm.

[emile turks]

thunderracing sells either a speedometer recalibration unit(permanently with same car, can't do 10 cars with same one) or reprogram it. I have Hypertech Power programmer which is worth 18HP/17 Ft Lbs of torque according to dyno results at rear wheels. There is no way of doing it mechnically though.

[LT19C1]

seems like that hypertech power programer can do a lot, maybe I should just bite the bullet and buy it...seems pretty useful for everything.

apparently it can even change the tempeture that the cooling fans come on at and go off at.

[emile turks]

yup, with a 160 stat, it kicks them on at 185 off at 175 OR
with a 180 stat(my 97 had stock in it) it kicks them on at 195, off at 185. Plus shift points/firmness and it is the quickest almost 20 hp I ever did. 15 min, sit on my butt and watch it download. The rev limiter is also adjustable from 5500-6600rpms. I love it and I can't even benefit from the transmission options.I waited until december when summit runs their 10% off sale and paid 315 instead of 345.