Speedometer reading wrong ?

[Z28ricer]

Heres the story, I bought a 93 hatch with an auto redtop already in it that was advertised as needing work, it had a rod knock, and i ended up replacing the entire setup with a full 5 speed motorset, the swap was originally done by zfever here in tampa, and i was less than impressed with quite a bit about it, the big one being when it hit boost the windshield wipers came up, the speedometer didnt work, but i figured that the cluster was broken.

I installed the motorset i got and modified the harness with it, the thing runs great and doesnt do anything stupid, only the speedometer works, but reads about half of actual speed. I havent been able to find much on if maybe the ecu has an output for cruise as some cars do with a speed signal of 1/2 the speedometer or a good enough pinout that doesnt just show the few things needed to make one run...

Any info is appreciated.