I think Tomas is asking about the 1974 'Cologne' GAA (or GA if you prefer!) engined Gp2 car. I seem to remember wheel widths different front and rear, but am pushed for time to read through my Ford books to confirm exact sizes. Quick check on Frank de Jong's 'Touring car Racing' website suggests 1974 car used 12 X 16 front, 15 X 16 rear, which sounds about right.
There are at least two genuine cars racing now, plus several replicas, so the info can't be that difficult to find. (If I remember) I'll ask ask some owners when they're racing at Dijon next month!
