Rod Hadfield’s 'Final Objective' 1955 Chevrolet Sports Coupe is the world’s best ever street machine.

Photographers: Helmut Mueller, Paul Tuzson, Mark Bean

With its twin-supercharged 27-litre V12 Rolls Royce Merlin certified at 3000hp, Rod Hadfield’s Final Objective is the world’s most powerful registered, street-driven car. Even Guinness World Records has recognised Rod’s effort.

This article on Rod’s Chev was originally published in the April 2003 issue of Street Machine

Disregarding the car’s world-record status, the ’55 is without doubt the most awesome car I’ve ever seen. I’m not making that statement lightly. My lifelong passion for all things automotive has taken me to some of the biggest shows in America and Japan not to mention filling my wardrobe to bursting point with hundreds of magazines covering the modified car scene from all over the planet. Final Objective eclipses all before it.

1955 Chevrolet Massive Attack frontEssentially the car is a 1955 Chevrolet Sports Coupe that’s underpinned by a fully fabricated box-section chassis, powered by a V12 Rolls-Royce Merlin – this one from a P51 Mustang. The huge engine feeds a two-speed Lenco and Chev C30 truck diff, which drives a pair of meaty Hoosier competition tyres mounted on massive 18-inch wide American Racing wheels. As staggering as these specs are, Final Objective is one of those cars that’s more than the sum of its parts. It’s also the end of a 15-year journey that has been Rod’s life-long obsession.

From the moment Rod took possession of the ’55 in 1986, he had the intention of stuffing it with the biggest, baddest, nastiest engine ever seen in a road-going car. He found a Centurion Tank V12 Meteor engine and it wasn’t long before he was hacking out the ’55’s firewall to make way for his massive new acquisition. However, later in the project an even more desirable powerplant presented itself – the supercharged, Rolls-Royce V12 Merlin that now resides in Final Objective’s incredible engine bay.

The DOHC, all-aluminium Merlin is one of the most famous aircraft engines, winning renown in the Spitfire and Hurricane, the Lancaster bomber and P51D Mustang. An engine of this heritage tied in well with Rod’s interest in all things military and goes a long way to explaining the Col. R. Hadfield stamp on the door.

Before starting the project in earnest, Rod and Castlemaine Rod Shop’s (CRS) Bill Mussett, who did much of the work, researched and studied a number of other V12-powered vehicles, including famous talk-show host Jay Leno’s V12-powered roadster in the US. They discovered that crankshaft speed and rotational direction were the first obstacles. Due to the supercharger set-up, the V12 is actually mounted in the ’55 back-to-front, so it rotates the wrong way. Secondly, the V12 was designed to drive a propeller at around 1800rpm and peaking at around 2600rpm, which is not much chop for street duties.

1955 Chevrolet Massive Attach side viewSolving both of these problems is a CRS-built transfer/step-up box that not only doubles the input speed to the two-speed Lenco gearbox but also reverses rotation. It’s an incredible piece of workmanship and engineering.

The carburettors were yet another headache. They originally pointed towards the ground and had to be modified by Superior Aviation to function in a conventional orientation and run happily on pump unleaded. Then, because the massive supercharger got in the way of a regular belt-drive arrangement, an accessory drive system had to be manufactured to run off the engine’s various external gear drives. To make things even more complicated CRS had to incorporate a special gearbox arrangement so the various accessories (power steering, fuel pump, alternators, and water pump) could be driven at different speeds.

Even though the engine is all aluminium, its sheer physical size made it obvious the completed ’55 was going to be pretty damned heavy – and the final figure is around 3500kg. To cope, two runs of 4×2-inch box-section steel were used to lay the foundations of the extensive chassis. The box section was internally galvanised to carry engine coolant between the four massive Aussie Desert Cooler radiators – two mounted in the boot and two up front. A grille at the base of the rear windscreen directs airflow to the double boot-mounted coolant radiators, along with the dual engine-oil coolers and the oil cooler for the Lenco transmission, which is likewise mounted in the boot.

Holding up the rear is a Geelong Differentials-prepared Chevrolet C30 truck diff modified to take Landcruiser hubs. The hubs are capable of carrying a vehicle of similar weight and their full-floating design was necessary to gain registration with the use of those monster 15×18 rear wheels. Those mega-wide rear Hoosiers are quite special. No one quite knows their origin or application, as they have an unusually high load rating and water-rejection tread pattern, making them perfect for the project.

 Servicing the treasured 27-litre (1650ci) Rolls Royce would have been impossible without a lift-off body, and Final Objective’s is all steel. This was to help make it strong enough to stop it flexing and cracking the very special windscreen that took Ray Charlton a month of Sundays to sandblast into shape, and to cope with the considerable weight of the boot-mounted fuel tank. There was also significant strengthening and re-engineering to keep the shell aligned and in shape when not mounted to the chassis. Part of that shell is the all-steel Mark Rye bonnet scoop neatly formed to resemble the Mustang’s original belly-pan air intake.

Waddington Street Rods and Restorations in Castlemaine was responsible for getting the body into shape, which included the delicate job of opening all the panel gaps to ensure they didn’t bind when the power and torque of the V12 Merlin started doing its best trying to spin the car on the crank. Part of Waddington’s meticulous body preparation included removing some rust and 45 years of wear ’n’ tear. Another example of Mark Rye’s excellent metal workmanship is the lowered front wheel arches, which were modified to more closely match the look of the rear.

 Waddington then sprayed the exterior in silver and covered everything else in same military green used in the original P51 fighter planes, before sanding, filling and painting the side-mount wood replica guns to look like the genuine article. Marty Everitt from Alphabet Signs is probably still seeing rivets in his sleep, after a solid seven months masking, remasking and masking again the 7000 rivet graphics and intricate Mustang paint scheme – including wing outline. He used detailed photography of a fully-restored P51D to recreate the fighter plane scheme which is based on the 352nd Fighter Group known as the Blue Nosed Bastards of Bodney, a unit based at an RAF airfield in eastern England, which earned itself a fine reputation in long-range bomber-escort work. Check out for its story.

Jump into one of the two hand-formed aluminium buckets and you’re confronted by a maze of switches, levers and gauges, some of them genuine WWII units. Starting the engine is a 20-minute undertaking, its many steps detailed on an engraved door-mounted plaque. Another highlight of the interior is the hand-made reproduction fighter-plane steering wheel, fitted with a quick-release splined hub to make it easier to get in and out.

 Those bitchin’-looking side-exit exhausts might look a lot like zoomies, but each individual pipe has its own built-in muffler to try to quieten the 3000hp (2238kW) beast. While loud on the outside, it’s even louder within, hence the need for headphones and an intercom set-up for the occupants. It might seem a bit like overkill, but the intercom is essential, as the passenger is responsible for monitoring a number of the vehicle’s vital systems.

The ’55’s braking system is as complex as the rest of the car. A dual-circuit master cylinder is used for the front brakes, while a second master cylinder works the rears. One of the team’s more elegant packaging solutions was to remote-mount the twin brake boosters behind the driver’s and passenger’s head and feed them a vacuum signal from a pump that bolts to the back of one alternator – the ’55 uses two for its 12/24V electrical system.

 Staying with heavy-duty truck bits, the C30 Chev front suspension uprights were hung off the chassis by tubular control arms. Steering duties are handled by a high-mounted XF power-steering box, which has had its output shaft modified to extend down to what is essentially a standard pitman set-up.

Once the military theme was settled on, Rod set about tirelessly collecting genuine WWII memorabilia (a task which took some eight years) to construct the Chev’s awesome show display. Original Rolls-Royce toolboxes were procured along with a genuine WWII aviation uniform. A kneeling mannequin was made to sit behind the replica machine gun.

Although Rod has 15 years and thousands of hours invested in the build, it was always his intention to register the car. He worked closely with automotive engineer Werner Ihle of Transport Industry Consultants, and the ASRF TAC Chairman Con Mantzaris, as well as VicRoads engineers to make sure it was going to be roadworthy. The incredibly high level of finish along with the faultless engineering was the principal factor in VicRoads’ decision to permit Final Objective full restricted registration.

While ducking down the shops is a bit beyond its scope, the ’55 has seen street duty a number of times since completion – including the documented outing for Guinness World Records, and a quick squirt down Northbourne Avenue on the way to an exhibition run on the Summernats burnout strip.

 It won Top Judged at Summernats in 2003 and garnered worldwide attention during its construction, so it will inevitably be wooing spectators at overseas events. Summernats Champion and Aussie ambassador is not a bad resume for any car.

Straight up, Rod acknowledges that much of Final Objective’s construction work was handled by Bill Mussett of Castlemaine Rod Shop (CRS) while he focused on keeping the business running to pay the bills.

Early on in the piece Ian Mapson put in the hard yards with Bill working on the car full time for the last five years. Lionel West is another CRS employee who spent many hours on the project, in fact every CRS staff member has worked on the car in one aspect or another. Rod estimates that along the way the equivalent of three of his 18-strong staff have been working on the car full time.

 As far as the V12 Merlin goes, finding written paraphernalia on how to tune, service and operate such an engine is near impossible and Rod is extremely thankful for the invaluable advice and help from John Wellwood in these areas. Without John’s help, which included useful hints such as the use of Penrite oil because of its particular suitability to the Merlin’s overhead cam configuration, that very special engine may not be running today.

While most of us would be chuffed to have built one or two high-end street machines, Rod Hadfield has built more than 30 during his 40-year involvement and obsession with modified cars and hot rods. Many of these projects are still in Rod’s possession and for just a dollar you can gaze at his huge array of cars and automotive memorabilia, such as the Hemi-powered T-roadster pictured above, at his Castlemaine museum.


Featured: April 2003

Cool info: Plenty of work is needed to keep a 3.5-tonne car under control. Suspension uses a CRS-built four-bar at the rear, with custom Koni coil-overs at each corner. Brakes are Ford F350 discs with six-spot calipers at the front and XF Falcon discs at the rear.
Paint: Blue/silver/yellow
Engine: V12 Rolls-Royce Merlin
Gearbox: Two-speed Lenco
Diff: Chev C30 truck
Wheels: American Racing
Interior: Hand-formed aluminium bucket seats, custom and WW2 instruments, on-board fire-extinguisher system



Photographers: Helmut Mueller, Paul Tuzson, Mark Bean