I found mine to be 10% out. 100mph on the clock reads 90 on the sat nav. This has been the case with every car I have put the sat nav in so far.
My car has 335,35,17.
Johnny
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.