Joined: 14 Aug 2006
|Posted: Tue Mar 31, 2020 11:01 am Post subject: The Ford Cortina GT500
|The Ford Cortina GT500
A car seldom remembered or even seen on our roads these days is the Ford Cortina GT500.
This version of the popular Cortina was the brainchild of Harry Firth,
Harry was effectionatley known as the "Old Fox" for his savy race tactics and was a Ford works driver in the mid 60's.
Later in his career Harry Firth developed the XR Falcon GT and won Bathurst in 1967 with Fred Gibson for Ford. Firth's approach to winning long distance races was to nurse the car along by being sympathetic with the machinery.
The Cortina GT500 was built for Ford Australia by Harry and his team to satisfy homologation rules to allow it to race in the Armstrong 500.
While the Lotus-Cortina would have fitted the requirements for the 500 mile race, the rules at the time stipulated that 250 model of the car to be entered in the race needed to have been imported and sold in Australia in order to qualify.
The race rules were much more relaxed for locally made or assembled motor vehicles with the requirement being for only 100 cars to be produced.
And so the Ford Cortina GT500 was created as a means of creating a suitable race car in Australia.
The donor car for the GT500 was the Ford Cortina GT 1500.
Harry Firth and his team then added a new cam, reshaped the combustion chamber, raising the compression to 9.5:1.
The flywheel was lightened, the head modified and the end bearings revised to allow better reliability at high engine revs.
With all of these modifications, the GT 500’s engine was capable of revving out to 7000rpm.
The biggest competition the Cortina GT500 faced at the Mount came from the BMC Mini.
Harry Firth came up with a number of additional modifications that ultimately provided the Ford Cortina GT500 with a huge advantage.
An auxiliary 8.5 litre fuel tank was added to the Cortina GT 500 and placed behind the rear window.
By having it’s own separate filler it allowed the GT500’s twin tanks to be filled at the same time thus reducing re-fuelling time during pit stops. The Mini Cooper S race cars also featured twin fuel tanks.
To keep the front disc brakes cool, large air scoops were added under the front bumper.
This modification also had a down-side with more water then able to hit the brakes in wet driving conditions on the track.
Harry’s Ford Cortina GT500 won the 1965 Armstrong 500 in a winning time of 7 hours, 16 minutes and 45 seconds. Fastest lap time by the Cortina was 3 minutes, 13.6 seconds and the Fastest speed for the CortinaGT 500 in the 1965 race was 120 mph.
By comparison the fastest lap at Mount Panorma for a V8 Supercar is 2:06 and set by David Reynolds in a Holden VF Commodore Supercar in 2016 with modern race cars achieving 180 mph + down Conrod Straight.
The Cortina GT 500 became a very dominant race car in Australia and in time the homologation rules were changed, with a increase lifting the minimum number of locally manufactured cars going up to match the minimum number of 250 vehicles that applied to imported models. The time of the Cortina’s dominance at the mount was coming to an end, making way for the legendary Falcon GT’s models.
The Ford Cortina was manufactured from 1962 to 1983 and produced in five generations as the Mark I through to Mark 5. Ir was eventually replaced by the Mazda 626–based Ford Telstar.
The Cortina name was inspired by the Italian ski resort Cortina d'Ampezzo, site of the 1956 Winter Olympics and several Cortinas were driven down the Cortina olympic bobsled run at the resort which was called Cortina Auto-Bobbing to provide publicity for the model.