Well, I've tried everything guys... Sent Speedo unit to MoMa and they told me unit is calibrated and functioning perfectly well at 200Hz, re-screened its face and all that. Vintage Motorsports installed the (according to Ferda) correct sending unit. But, the needle keeps moving around.....about 1/2 the real speed. I noticed that sometimes it jumps up and down and then it settles down to no speed (even though I am moving..), some other times it jumps constantly. Ferda believes it is a wirring or contact issue, since the sending unit is new and the speedo has been checked. I am looking for things to look for when I raise her up on a lift (?) ... need to hear from you guys...before I buy an ugly GPS unit to check my speed in the Hill Country. Any advices from the experts out there? Many thanks.