The decision was made in 1968 to grid up a special version of the upcoming LC Torana to replace the hulking 350ci Monaros. Harry Firth alias the Silver Fox was given a GTR and told to go to town on it. Harry was not only a brilliant racer and a shrewd Team Manager but he knew where to go for expert advice and that was Dyno Dave Bennett from Perfectune. Harry placed an initial order of 250 cylinder heads from Dave.
The first XU-1 was announced in August 1970 with Holden downplaying the racing aspirations of the XU-1. It read as follows;
GMH today announced the Torana GTR XU-1, an additional model in the LC Torana range introduced in October last year. ”
The rest of the blurb occupied little space. But the specs themselves demanded five times as much paper space. Fitted with three carburettors 186ci engine, the XU-1 is in fact a higher performance version of the GTR sports sedan. The XU-1 has been developed to meet strong demand for such a vehicle from motoring enthusiasts. An initial batch of 700 will be produced to meet initial demand, to be followed by further production if subsequent demand re-warrants. The increased engine capacity of the XU-1 has resulted in numerous refinements designed to improve overall handling and performance. Front and rear suspension modifications, larger disc brakes with an increased capacity brake booster, front and rear spoilers and a greater radiator cooling capacity are the major items.
The XU-1 is fitted with a 17 gallon fuel tank to increase the car’s touring range. Principal external features are the rear spoiler, GTR XU-1 decals, and exclusive bold colour range. Nowhere is mention made of Mount Panorama, nor does it say many of the motoring enthusiasts would want to race their XU-1s. While the XU-1 was a purpose built race car Holden was not about to admit this to the general public. That was back in 1970.
Every aspect of the XU-1s design cried Bathurst from the 17 gallon fuel tank to the design of the front spoiler, which not only added stability but deflected air onto the front discs. The standard LSD was 3.36, ideal for pulling up Mt Panorama but a more relaxed 3.08 was optional. In 1970 GMH still did not have its own 4 speed box so the XU-1 had to make do with the Opel box that was prone to failure. If the LC XU-1 had one weakness it was the gearbox. At 125 MPH the Torana was still 400 rpm short of the red zone. Zenith supplied the triple 1.5” side draught carbies, giving the Maximum power of 160bhp at 5200rpm, while torque was 190ft/lb at 3600rpm. With still more scope for development Harry Firth masterminded some mods just in time for the 1971 Hardie-Ferodo. These included a heavier clutch and thicker front brake discs. A reworked head, new pistons and a trickier bump stick (cam) enabled the motor to produce an extra 20hp at a sky high 6000rpm.
Only five months after the introduction of the 1971 Bathurst special, came the LJ model. Naturally it was changed in styling and interior details to match the other LJ Toranas. It’s exterior was cleaner, crispier and less boy racer than the LC’s. The interior was also neater, and you could even order hounds tooth check cloth trim. However the big news was all of a mechanical nature. In place of the 186ci the LJ acquired the HQ’s 202ci. But this application was more serious than in the family Kingswood. The compression ratio was 10.3:1 which was .03 higher than the Bathurst 71 LC version. Triple 1.75” Stromberg’s were used instead of the Zeniths. Straight out of the box this model, this model developed 190 horsepower at 5600rpm and peak torque was 200ft/lb at 4000 rpm.
There were headlines in the transmission department too. Gone was the fragile Opel, as GMH had developed it’s own all Australian four slot, known as the M21. Like the standard GTR, the XU-1 came with a LSD running 3.36 gears but you could order 3.08 ratio.
In the early 70s many competitors drove their series production race cars to the track. The LJ XU-1 could tackle the trip from Melbourne to Bathurst in relative comfort. It was more civilised, less rough around the edges but just as fierce in performance, handling and braking. It was a billy cart you could live with.
During 1972, Harry Firth was developing a GTR XU-1 V8, it was a popular myth that this car was going to be called an XU-2 as it was always going to be called a GTR XU-1 V8, with the XU-2 tag considered for the upcoming LH Torana. The great muscle car scare of 1972 put an end to the GTR XU-1 V8 with three being built by Harry Firth, and still some way off from being reality when the muscle car scare came about.
Bathurst 1972 meant squeezing more life out of the old ever-loving red six, HX camshaft, light flywheel, alloy wheels, revised suspension, balanced and blueprinted saw 212 horsepower come from the trusty six. This allowed Peter Brock to notch up his first Bathurst victory.
In 1973 the LJ XU-1 received its last rework. GMH waved the TLC wand over 150 cars . Perry�s developed a special tubular exhaust manifold and good old Dyno Dave of Yella Terra fame administered larger valves and various beefed up engine bits, heavy duty axles and improved brakes rounded out the picture for 1973 and the swansong for the GTR XU-1. Peter Brock could have easily won his second Bathurst in 1973 but a wrong call saw his Co-Driver Doug Chivas run out of fuel and he had to push the car back into the pits costing them any chance of victory.