Afternoon I'm wondering if someone could help , I'm carrying out a project on a coupe and am after a couple measurements firstly wheel base, centre of front wheel to centre of rear and also centre of front wheel to edge of frount sill and the same with the rear wheel any help would be much appreciated thanks Simon

Hi Simon & welcome
The wheelbase (as described on the spec sheet supplied by GTM in the 80’s) is 84”.
You may find more of the info you require in this link:
http://www.lightauto.com/gtm.html

I emailed Simon earlier with some measurements from my car

I also emailed Simon, but will stick them on here as a comparison for others.

This was the Right hand side of the car, really should of measured both sides and took the average

Front wheel centre to sill = 360mm
Front wheel to rear wheel centres = 2142mm (sales material says 2133.6 so 8mm out)
Rear wheel to sill = 330mm

These were taken with a plump bob to a fixed rule, so should be close.

Be interested to see others measurement as I guess setting the caster at the front will make a little difference to the distance.

Mine were taken from passenger side. I held a rule flat against the end of the sill and then with a helper measured with a tape measure.

Front wheel centre to sill = 335mm
Front wheel to rear wheel centres = 2130mm
Rear wheel to sill = 320mm

I think my car has Metro front hubs, I don't if that makes any difference to that measurement.