The Phase IV & the Supercar Scare

GT Information Article - 5a


The "Supercar Scare" – a journalistic beat-up of hi-performance production cars from all of the big three car manufacturers – not only caused the demise of the GTHO as a production model, but was also responsible for a change in the regulations for Touring Car racing.  The XA GTHO Phase IV, was to be the ultimate road and race car to be built by Ford in Australia.  Unfortunately, just as production was about to start, a number of well-known motoring journalists started a smear campaign against the next generation of “specials” being developed by the three major manufacturers – the Phase IV Falcon GTHO, the XU-2 Torana V8 and the E55 Charger V8.  In their articles, these journalists claimed that each of the vehicles being developed could top 160 MPH in road trim and in doing so would represent a significant danger to the Australian motoring population by causing death and mayhem on public roads.  Essentially... "bullets on wheels"!!!

But in true journalistic fashion, the old adage of “never let the truth get in the way of a good story” was well in force.  By concentrating only on guesstimates of the top speed potential of the cars (the road going Phase IV's top speed was actually only around 150 MPH), the question of primary safety was generally overlooked. Although able to travel very quickly in a straight line, these cars were also designed for safety, with the handling, braking, steering and road-holding commensurate with the speed potential of the vehicle.  If the truth be told, the greatest danger on the Australian roads at the time was the typical family sedan with drum brakes, cross-ply tyres and built in under-steer – unsafe at any speed in my opinion.

In the end, the journalists whipped up sufficient negative public opinion, that the Government of the day decided that these cars should not be made available to the public, even threatening the manufactures with the cancellation of fleet contracts, should the vehicles be built.  Due to the obvious financial ramifications involved, the manufacturers had no choice and cancelled production. 


So how special was the Phase IV going to be?  Externally, they would have been no different from the standard XAGT four door.  That’s right, all Phase IVs were to have been four door sedans.  The only giveaway, would have been the special Bathurst Globe mags, which although designed for the Phase IV, eventually found there way on to the Phase IIIs.  Apart from looking good, these mags provided a number of benefits.  These wheels were stronger than the steel versions, they vastly reduced unsprung weight – which helps with steering and handling – and they also cut brake operating temperatures down from 840˚C to 450˚C.  Mechanically however, the Phase IV was very similar to the Phase III.  The brakes were the same, with the front disc and rear finned drum setup being carried over, as was the 36 gallon fuel tank.  Although the front springs remained the same as the Phase III, the wider track of the XA model and new wheels had the side effect of softening the spring rating for a better ride.  A newly developed rear spring setup provided greater roll stiffness, allowing the rear bar to be removed.  Combined with a slightly softer front sway bar, the Phase IV was far more neutral in its roadholding. 

In the engine department, a number of changes were made. Most significant were the revisions to the cylinder heads, where larger valves and changes to the shape of the combustion chambers helped improve volumetric efficiency.  Although these changes reduced the compression ratio slightly, they helped improve torque and more importantly, allowed it to come in a full 1000 RPMs lower in the rev range.  This made the engine much more tractable and as a side benefit, more fuel efficient. The “Buddy-Bar”aluminium inlet manifold – that was available through Ford as a performance upgrade – were also being considered, but never actually made it into production.  Changes to the exhaust system also helped improve the spread of torque over a greater rev range, while a new radiator fan – which incorporated blades that flatten at high RPMs – helped minimise horsepower losses.  While the camshaft and carburettor remained the same, the bigger radiator from air-conditioned Falcons was used to provide greater cooling.

As with the Phase III, a rev limiter was also incorporated, but unlike the bulky module bolted to the firewall in the Phase III, the Phase IV had its rev limiter built into the rotor button of the Bosch twin-point distributor. When the engine was revved to the 6200 RPM limit, centrifugal force would cause a small weight to form a contact within the rotor button.  The resultant short circuit would disrupt the spark being fed to the plugs and limit the engine from revving further.  Porche used the same system in their cars.

To help the problem of oil surge, encounted during high speed cornering, “ears” were welded to the sides of the sumps, to not only increase the capacity from eight to eleven pints, but also to help concentrate the volume of oil around the oil pump pickup.  Due to the improved torque characteristics of the engine, the “detroit locker” diff incorporated a taller ratio of 3.00:1 (as against 3.25:1 for the standard Phase III) and was driven through a standard wide ratio gearbox.  This provided the Phase IV with a gearing of 24.4 MPH/1000 RPM in top, which converts to 151 MPH at the 6200 RPM limit.

Total production of Phase IVs was to be 200, with 100 to be built at the end of June 1972 with the remaining 100 at the end of July.  As we all know, however, only four were actually built – one pre-production model (which is the only one actually plated as a GTHO) and three racing versions (one each for Allan Moffat and Fred Gibson and a spare).  Of these however, only three survive – two of the racecars and the production model.

After full production of the Phase IV was cancelled, Ford decided to sell off the four cars.  The spare car – which had the least race preparation – initially went to John Goss via McLeod Ford, who assembled the car for road use.  In 1977 Fred Gibson test drove the car (then with only 1900 miles on the clock) for Racing Car News.  Fred’s verdict was that it was a much better and more sophisticated car than the Phase III and would have developed into a great racecar.

The second racecar was delivered to Bruce Hodgson, who successfully rallied the car over a number of years, even though this type of motorsport was light years away from its intended purpose.  Unfortunately a head on with a Commodore destroyed the car and although the wreck is believed to exist, the car is unlikely to re-appear.  The first and most developed of the three race cars, was originally sold by Howard Marsden to Keith Goodall in Townsville and currently resides in the Bowden collection on the Sunshine Coast – this car being the one that is pictured in most of the magazine articles. The production model, is still believed to be owned by a dentist in Sydney who must have been the astute buyer, when offered for sale in 1978 at a car yard.