Marcos Maniacs

--- In MarcosManiacs@y..., "Don Lattimer" <donlattimer@p...> wrote:
Hi Don,
Normally you would change the speedometer drive gear in the 
transmission first.  Most transmissions have a variety of speedometer 
drive gears to match the various rear end ratios that are used in the 
various cars that use that particular transmission.  My Marcos, for 
example, has 4 different speedometer drive gears for the Volvo 
Transmission.  With these 4 gears I can find one that is close for the 
3.9, 3.77 and 3.55 rear end ratios that are used in the Cortina rear 
ends.  I'm sure that your transmission is the same although it may be 
harder to get the parts.
Mike Denman
1966 Marcos 1800
Chassis # 4079
> 
> My speedo reads 70mph when actually I'm doing 62 mph.  Checked by my 
> GPS.  What needs to be changed?  I suppose I need to figure out what 
> the rear axle ratio is first.  How can I do that physically?  There 
> must be a way to measure the tire circumference, etc.  Any 
> suggestions??
> 
> Don Lattimer
> #3M5759 V6
> Willits, CA