digital dash MPH reading wrong help

[drive805]

i have an 85 Gn digital dash... i had the casper upgrade when it was fixed...
when i bought the car it had 4:11 gears.... i installed 3:42 gear now the issue...
digital dash reads 30-32 MPH at 65 and reads 58 KPH at 65 scan master reads 30MPH at 65 also ....
how do i change to get digital dash to read correctly TIA

 

[QUIP'6']

They might have changed the speedometer gauge

Sent from my SCH-I100 using Turbo Buick

 

[trbojo]

you're going to have to get a different speedo gear for the trans.