From looking over my 6-cylinder Cortina, I can confirm the following differences from the 4-cylinder.
- Different firewall.
- Tubular cross member under gearbox.
- Crossflow radiator which is also cut into the front bar.
- Bonnet bulge
- 4 headlights (TC only)
As for that paragraph on Wikipedia. shesh! It appears there are plenty of armchair experts regarding the six cylinder Cortina getting around the net and I can tell you they don't roll at all. Understeer is all that there is.