We recently lost the Mk1 Cortina forum and fordcortina.com.au sites and with them alot of info and chat on the Mk1 Cortina GT500.
I thought I'd start this thread to gather back some of this info and shed some light on this model.
Firstly I'm no expert on the subject and welcome corrections, contributions and chat on this model.
The Cortina GT500
After the success of the Cortina GT's in the 1963/64 Armstrong 500 Harry Firth was commissioned to build a new homologation variant to take on the threat of the Mini's.
With a few exceptions of cars bought in for motorsport Australian Cortina GT's were typically 4 door sedans. The GT500 was based on the 2 door shell.
Under the rules of the time imported cars required 250 items whereas locally built cars required a number of 100.
Reported numbers of the GT500's built vary from 100 to 120.
The GT500 placed first and second in the 1965 race in the hands of Bo Seton/ Midge Bosworth and Bruce McPhee/ Barry Mulholland. This was mainly due to having to take less stops with the fitment of an extra 8 3/4 gallon fuel tank taking capacity up to 17 gallons in total.
Identification
GT500's were assigned the model code 27134.
Externally they received a '500' badge on the rear quarter in front the GT badge.
There was twin fillers for the auxiliary tank behind the rear windows and the original rear filler was crudely blanked off.
There was also aluminium brake ducts on the front of the car.
To allow the car to run the race without an air filter one was supplied, but in a brown paper bag in the boot upon purchase.
Amongst other modifications the 1500GT engine had a higher compression ratio, ported head, revised camshaft and copper/ asbestos head gasket.
Specs taken from here
https://www.uniquecarsandparts.com.a...specifications
Capacity: 1498cc
Type: Conventional, watercooled four stroke, reciprocating piston type, 4 cylinders, OHV Cross-Flow Bowl-In-Piston featuring 5 main bearing cast-iron crank-shaft, with integral weights dynamically balanced
Configuration: Front mounted, longitudinal, inline
Head: Pushrod and rocker actuated ohv with integral guides cast into fully machined cast iron ported and polished cylinder head, with special copper asbestos head gasket.
Other modifications: Dynamically balanced 5 bearing cast iron crankshaft with integral weights running in new type steel back copper lead bearing liners. Lightened and balanced flywheel and clutch assembly together with a special crankshaft pulley of machined steel. Connecting rods and H-section forging with steel backed new type copper lead bearing liners. Special conrod bolts with enlarged bolt-head and and lock tabs. Camshaft ground to revised specification. Cast aluminium alloy inlet manifold and dual barrel down draught carburettor with revised chokes and jetting. 3-point rubber suspension of engine and gearbox.
Fuel System: Single dual barrel down-draught Weber with differential throttle opening. Modified choke, emulsion and jet sizes
Bore and Stroke: 3.187 x 2.86 inches
Power: 95.0bhp at 6000rpm
Torque: 101.5lb-ft (Nm) at 3600rpm
Compression Ratio: 9.5:1