speedcal

My First Post here..hope it's not too long. I got a 96 GT with t-45. I swapped gears to 3.73 and bought a speedcal to fix the speedo. Install went well and it worked fine until you hit 55 mph where the speedometer goes to zero. I found the alternate bank 2 dip switch setting of "0100000"...

I have a dallas mustang speedcal in my car with 3.73 gears. The speedcal was in it when I bought it but now my speedometer goes from reading 0 up to something like 100mph then back down to 0 while i'm at a stop. The speedometer also reads about 6 or 7 mph faster than i'm actually going until I...