Murray's 1970 Plymouth Road Runner Superbird - FEATURE

NASCAR's muscle car era culminated in the infamous 1969-1970 'Aero Wars', which came to a head - and an end - with 1970's Plymouth Road Runner Superbird. Powered by a ferocious 426 cubic-inch Hemi big-block V8, the 1969 Dodge Charger Daytona and follow-up Superbird were the first muscle cars to roar through the 200mph mark and took MoPar's fight back to the Ford Torino Talledegas and Mercury Cyclone Spoiler IIs.

Murray Markwell of Packenham in Victoria knows the lore behind these legends and his 1970 Superbird is a tribute to that golden era.

"I have an original advert in my office for the Superbird. It says, 'Superbird, too fast? Not a Chance'," Murray laughs. "I guess, for me, that sums up the decadence of 1960s USA that we missed out on here in sleepy, conservative old Oz."

While it looks the part, with its NASCAR-style steel "police" wheels and decals, Murray's car actually started life as a lesser (but still hugely desirable) Plymouth GTX, which was kitted out with all genuine Superbird parts by a Plymouth dealer back in the early '70s.

"I found it on a trip to the USA in 2008 and had to have it," says the man behind Southern Customs. "It was a well-known car in the US from a deceased estate in Arizona, with only 65,000 miles on it."

The late '60s-early '70s GTX, Superbird and Road Runner were all based off Plymouth's mid-sized coupe; the Belvedere/Satellite. Riding on the B-body platform, the Belvedere was a cheaper, more youth-oriented variant of Dodge's Charger. The GTX followed the Satellite route of being better trimmed and equipped for more luxurious intent, while the Road Runner was closer to the Belvedere, taking that basic platform and using it for a stripped down and high-horsepower, but still affordable muscle car.

Along with a range of huge V8 engines and rainbow of lurid paint colours, Plymouth even licensed the "meep-meep" sound of the cartoon roadrunner from Warner Brothers to use for the horn. An immediate hit on debut in 1968, the Road Runner has become one of the most desirable muscle cars of the era. However, the Superbird (and its Charger Daytona forebear) was an altogether more serious beast.

The Charger Daytona was reputed to be the first American car designed using computers and a wind tunnel, as the manufacturers chased glory in NASCAR's Grand National series. The Daytona's elongated wedge nose was made from fibreglass and added 19-inches to the front of a regular Dodge Charger. It was designed to enclose the standard, aerodynamically inefficient headlight, bumper and grille set-up.

The Superbird team used the Daytona's experiences in races through 1969 to refine many aspects of the aero package, like the reverse-facing scoops on the top of the front guards, which cover holes drilled to eliminate pressure areas in the front wheel-wells.

Interestingly, the Belvedere didn't readily accept the Daytona nosecone (which was steel in the roadgoing cars), so the Road Runner Superbird actually features a modified bonnet and front guards from a Dodge Coronet. As it contains all the headlight mechanisms, Murray says there are over 120 individual pieces to the Superbird's nosecone which, at a $30,000 replacement cost, is a seriously valuable item these days.

That massive rear wing differs between the two cars, too. The Superbird's has a broader base, and runs at a slightly different angle from the Daytona. Although the huge hoop was thought to have been designed to eliminate turbulence behind the rear window, it was revealed in the 1990s that the shape and position was determined by much more practical considerations - to allow the bootlid to be opened! Still, it made the Mopar machines instantly recognisable compared to the sleeker Ford and Mercury race cars.

Chrysler's aero monsters became the posterchildren of NASCAR high-speed hijinks, especially as they could be bought by cashed-up kids from a regular Plymouth or Dodge dealer. While the cars that legends like Richard Petty and Bobby Isaacs drove on Sunday were hand-built, race-only machines, the NASCAR rules of the time still required a number of examples to be built for road use.

While Dodge only had to build 500 Daytonas for 1969, a rule change for 1970 meant Plymouth had to build one Road Runner Superbird for every two dealers in the US in order to homologate it for that year's NASCAR season. This is how 1,920 (or 1,935 or 1,971, depending on the source) Superbirds came to be built. Today, it's estimated only 1,000 of that total survive.

Buyers back then had a choice of two 440 cubic-inch Super Commando V8s (single 4-barrel carburetor, or hot sauce triple 2-barrel '6-pak'), as well as the legendary 426 cubic-inch Hemi. Only 135 Hemi Superbirds and 716 6-pak 440 Superbirds were built, with the remainder sold as basic 4-barrel 440s.

The high-compression, lumpy and decidedly un-street-friendly Hemi was an expensive option geared towards NASCAR racers. Murray's Superbird (it's on the Superbird register, so we reckon it is kosher to call it one) packs a 6-pack 440, though the RB V8 was built back in the day for drag racing, which explains the fully manualised 727 Torqueflite three-speed auto.

Drag racing one of these rare, exotic Mopars might seem strange, given there would be no aero benefit over 400m, compared to the extra weight the nose kit and spoiler adds to the car. However, Murray's car did do quarter mile runs during its time in the US, and ran consistent low 10s thanks to a bunch more herbs than any 440 had when it left the factory.

With a steel crank, I-beam con rods, forged +60-thou pistons and super-choppy 312-degree cam, the block has been filled with all the goodies needed to make serious grunt. Other modifications over standard are the three-inch headers and Moroso sump and oil pump, ensuring the big 7.2 litre doesn't starve and run a bearing.

While most drag racers or NASCAR racers would spec "dual quads" for their big-blocks, Murray's unique Superbird retains its factory 6-pak set-up. The trio of two-barrel carburetors is generally favoured for high-performance street cars rather than the twin-4-barrel dual-quad set-up as the quads suit high-RPM, flat-out engine operation and had a reputation for fouling plugs and being pigs to drive around town.

Chrysler got around those problems with the 6-pak by using a single 350cfm Holley 2bbl carburetor in the middle to feed the motor on light load situations (where not much fuel or air is required). When the go pedal is mashed, however, two extra 500cfm Holley 2bbls open up, delivering a total of 1350cfm of air and several Middle Eastern countries' worth of petrol!

Ultimately, it was their restriction (virtually an exclusion) in NASCAR competition that killed the Daytona and Superbird. Yes, the Superbird's legendary 300+kph speed actually counted against it. NASCAR feared the cars' outpacing tyre and safety technology, frighteningly demonstrated by Richard Petty's horrendous crash at the Rebel 400 at Darlington. The governing body mandated that, from 1971, aero cars would be restricted to five-litre V8s (down from the previous seven-litre motors) or have to carry massive weight penalties. With the exception of a handful of privateers, this ended the aero car era at a stroke.

The road cars struggled to find buyers, too, due largely to their voracious fuel thirst, sky-high insurance premiums and radical styling. While it looked great on the track, that styling was considered too extreme compared to the simpler, cheaper and more muscular Roadrunner and Charger offerings. The arrival of the larger, more luxurious and more conventionally-styled E-Body Challenger and Barracuda for 1970 put another nail into the coffin of the Daytona/Superbird.

The result was that many Superbirds remained unsold for years after NASCAR banned the be-winged monsters and, incredible as it may seem today, some dealers allegedly removed the wing and nosecone and returned them to standard Road Runner spec in order to shift them from showroom floors.
 
Today, the Superbird is an icon, and not just with guys of Murray's vintage. "It scares children until they realise it is a red version of the 'King' from the movie 'Cars'," Murray says of his 'Sunday car'. "And then they can't keep away!"

Thankfully, we have people like Murray who are willing to preserve cars like this as a time capsule of the days when petrol was cheap, sex was safe and racing was dangerous.

Text: Frank Slacks
Images: Dan Smith

Murray's 1970 Plymouth Superbird - basic specs

Engine type: 440RB
Capacity: +0.060 inch
Crank: Steel
Rods: I Beam
Pistons: Forged
Cam: 312 degree
Intake: factory 6 pak
ECU/Carburettor: 2 x 500 Holley and 1 x 350 Holley
Cooling: Factory Superbird
Sump: Moroso
Oil pump: Moroso
Exhaust: 3 inch with open header plates

Transmission: 727 Reverse Valve Body Automatic
Tailshaft: 1350
Diff: 4:11 Dana 60 Posi

Suspension: (Front): Factory    
                 (Rear): Factory
Chassis: Chassis Connectors fitted

Steering: Factory power-assisted

Brakes: (Front): Wilwood 4 spot
          (Rear): 11 inch drum
Master Cylinder: Wilwood

Wheels: (Front): Mopar Police 15 x 8
           (Rear): Mopar Police 15 x 10
Tyres: (Front): 255/60/15 Street Slicks
          (Rear): 295/55/15 Street Slicks

Paint /Interior/Roof: Tor Red/Black Trim/Black Roof