Superformance MK2 Slab Side

Superformance is proud to announce the availability of our newest model the Superformance MKII Slab Side – designed to emulate the great Cobra 289 street cars from that nostalgic golden era of racing in the 1960s. Unlike most competitors, the MKII Slab Side is built on the successful Tojeiro-styled round tube chassis and features an authentic transverse leaf spring suspension to give owners an exceptionally authentic driving experience. Through our exclusive agreement with Carroll Shelby, the MKII Slab Side is the latest licensed Shelby product in the Superformance lineup.

Dimensions & Capacities

Wheelbase	90"
Length	151.5"
Height (Top of screen)	45"
Width (Overall)	72"
Track Front	53"
Track Rear	53"
Fuel Tank	14 gal.
Front Wheels	15" Dayton 70 spoke knock off
Rear Wheels	15" Dayton 70 spoke knock off
Tires-Front	205/70 R15
Tires-Rear	205/70 R15
ZF Limited slip differential	Ratio 3:46:1
Salisbury differential	Ratio 3:54:1
Chassis	Round Tube
Body	Fiberglass with steel tube reinforcements
Body Reinforcements	Beneath doors, hood and trunk
Front Suspension	Transverse leaf spring, Spax adjustable shocks
Rear Suspension	Transverse leaf spring, Spax adjustable shocks
Steering	Rack and pinion
Pedal Box	¾ clutch master cylinder, 2x ¾ brake master cylinders with balance bar
Front Brakes	Wilwood 4 pot dynalite
Rear Brakes	Wilwood 2 pot with handbrake incorporated
Exhaust system	Twin pipe rear exit
Instrumentation	Stewart Warner
Interior	Motolita steering wheel, leather / vinyl seats
Weather	Optional soft top, side screens and tonneau cover
Recommended engine & transmission	Ford 302 based with TKO 600

Standard Equipment

• Show quality two-stage paint finishes.
• Hand laminated fiberglass body with reinforcing inserts.
• Heavy duty TIG welded 3" Tojeiro style frame chassis.
• Transverse leaf spring style suspension.
• Salisbury limited slip differential.
• Willwood® front and rear disc brakes with double master cylinders.
• Original style Dayton wire wheels with 15” tires.
• Original style shifter and hand brake lever.
• Black carpeted interior.
• Sun Visors and wind wings.
• Original style latch-lock seat belts.
• Moto - Lita wooden steering wheel.
• Original style fuel filler.
• Aluminum hi-performance radiator, shroud and fan.
• Stainless steel fuel tank. 14 gal.
• Original style gauges (Stewart Warner) and switches.

Options

• Exhaust and headers to accommodate Ford based V8 engine.
• Soft top and side curtains.
• Tonneau cover.
• Side and rear view mirrors.
• Leather seating surfaces (drivers and passanger adjusts).
• Harrison expansion over flow tank.
• Differential oil cooler.
• Auxiliary Racing tank.
• Stainless steel quick lifts.
• Door map pockets.
• Fuel transfer valve.

The Chassis

The Chassis is the original John Tojero designed 3” tubular rail ladder with cross-member. This chassis is reproduced using drawings obtained from AC cars and also implements the necessary changes to utilize rack and pinion steering . The 3” tubes are tig and mig welded to guarantee a safer and stronger chassis. This is much stronger than the arc and gas welded originals. Pain staking efforts were made to reproduce the chassis as close to an original as possible while incorporating a few modern improvements, like inserting a 3" square tube through the main rails to prevent flexing. Building the cars with a meticulous eye on authenticity took time, but this resulted in a superior driving experience.

The Suspension

To compliment an original chassis you need to follow the same rules when it comes to the suspension. It had to be period correct, or as close as possible. The original slab side had a transverse leaf spring style suspension which requires different length springs to change camber settings we decided to use heim joints which were used on some of the original competition cars.

Another change with regards to safety was to add an additional pick-up point to the chassis to increase the shear strength of the bolt passing through the lower control arm rose joint or poly-bushed rod end. The original springs were made of thinner steel than that available today. In an effort to keep compression rate the same, this car comes with one blade less and “free camber” was changed to keep the ride heights equal from front to rear. This insistence on authenticity means that owners of a Superformance MKII roadster will have virtually the same driving experience as the original.

The Body

The Superformance MKII roadster bodywork replicates the later of the 289`s which incorporated modifications to fender flares that will accommodate the slightly wider tires fitted onto chrome wire wheels. One of the improvements made by Hi tech was that the footwells were tweaked so that the taller North Americans can now sit comfortably.

The Interior

Again, attention to small details like the replication of the glove box knob and the correct use of gauges make this car stand out from the others. A Side screen pocket is fitted behind the seats on the rear bulkhead and door map pockets are also incorporated in the doors. Lush carpeting finishes off the cabin for a comfortable feel on the road.

The Powertrains

An Original would have probably been a 289 with a B.W T10. Today, the recommendation would be a 289/302 based engine with a more modern Tremec TKO or similar transmission.

History and Origins

The Shelby Cobras were based on an aging, but light and strong, British roadster, the AC Ace. AC cars were at this stage trying to source different engines with the Buick/Rover V8 being one of them. Initially, the 260 cubic inch small block Ford was adopted and after 75 cars an upgraded 289 was fitted. Some significant body changes took place with this modification. Front fender louvered side air vents were fitted and the nose altered to allow more air in.

The chassis was also tweaked by Alan Turner at the AC cars factory. Heavier gauge tubing with extra cross bracing was used and because the rear brakes had been moved from inboard to outboard, the differential area could be modified and strengthened as well. The first 126 frames used the same front suspension tower as the Ace but when the change to rack and pinion steering took place, a different type of front shock tower was used. This allowed for further strengthening.

The change from worm and sector to rack and pinion transformed the handling of these cars. At the same time the bottom control arm pick up points were able to be repositioned. Originally the 3" tubing was all arc welded whilst the body framework, consisting of ¾" and 1" steel tubing, was gas welded. 1 ½" tubing was used to strengthen the scuttle area. Today we use state of the art technology that has vastly improved on these methods, although hopefully none of the charm has been lost.

The John Tojeiro designed 3” tubular rail and cross member ladder style chassis, with front and rear suspension towers welded to it, started off life under a Cliff Davis 2-liter special in 1953. The little red Ferrari 166 barchetta look-a-like body placed on top of this chassis proved to be a formidable force in the local club racing events... so much so that AC cars decided to buy the design when it was offered to them.

The first Aces used a Weller-designed ohc engine and then later the more efficient Bristol BMW based 2.0-liter unit. When Bristol stopped producing these in 1961, AC tried various other options including the 2.6-liter Ford Zephyr engine tuned by Ken Rudd. This motor was fitted for a short while and because of the extra weight and horsepower, strengthening of the chassis and slight body changes were done. The nose and hood line were changed, (lowered) improving aerodynamics. From these changes the Ace 2.6 evolved.

It was at about this point that AC's owner, Charles Hurlock, was approached by Carroll Shelby to use a Ford V8 in the Ace chassis. The result was the AC Cobra in 1962. Production of the Ace ended that same year, but the AC – and later Shelby – Cobra went on to win Le Mans and become the fastest "production" car in the world. It also become one of the most recognizable and admired sports cars of all time.