Assuming 165 hp at the wheels (estimated from
http://www.mk5cortinaestate.co.uk/calculator4.php) and A=2.3 sq m (googled up somewhere) and Cd= 0.27
the max speed would be 242 km/h = 150.5 mph.
If anyone gives me more reliable figures for A and whp, I can recalculate.
Another calculation should be done using rev limit, gear and drive ratios, and tire sizes.
EDIT using 1.225 air density from wikipedia, instead of 1.3, I am getting 247 km/h = 153.5 mph.