Speedo Off?

Hey all since I did my KB, my speedo is off. I have 3.73's, 18 in rims, and autometer's gauge pod. I have a speedcal that was calibrated to the wheels and gears, before the sc and was working fine. Is it possible that the autometer gauges are off, or did the kb chip screw it up..how do I fix it? It's dead on at 30, 5 under at 40, 10 under at 50 and 60, then above 70 I'm actually almost doing 90. Any sugestions.
Thanks

Yeah your probably right, I'm actually going to set the speed cal to factory gear setting, since kb should have already corrected for the gears like you said, but I'll still correct for tire and rim size, that hopefull should work thanks for jump starting my brain