1991 suburban Speedometer Calibration

[HAZZARDJOHN]

I have a 1991 Suburban 4x4 and I am coming from the Impala SS LT1 world where you recalibrate the Speedo with a programmer. How do I fix the speedo when I upgrade to 31" tires? I tried searching but nothing came up. for a 1991.

 

[RetroC10Sport]

These trucks use a DRAC module.

http://www.tbichips.com/drac/

There's a couple of good site out there on how to make calibrations. I think there's someone here that's selling a modified DRAC as well.

 

[HAZZARDJOHN]

These trucks use a DRAC module.

http://www.tbichips.com/drac/

There's a couple of good site out there on how to make calibrations. I think there's someone here that's selling a modified DRAC as well.

Does anyone know who that'd be?

 

[RetroC10Sport]

http://www.gmsquarebody.com/forum/member.php?u=2094

X-cabsquarebody.

 

[Old77]

Drac module calibration
http://www.gmsquarebody.com/forum/showthread.php?t=6250