ok , having read the book , and now aquired my chassis - wheres the technical data sheet telling me the track , wheelbase , width etc etc .

my donor car has a width of 66.5 inches - (max across the wheels)how does this compare with the ford inspired ones .

It's still in your calculator, bursting to get out!

well , i was guessing that it would be something like that - Do the sierra based kits share the same track as the donor car or not ?

Depends which kit.

Luego Velocity used Escort track with Sierra donor (shotened rear driveshafts).
Velocity XT uses Sierra track.
MK uses Sierra track. (IIRC)

HTH,

James