’63 PONTIAC SD-421: SWISS CHEESE LITE!

Production of lightweight ’63 Super-Duty Pontiacs was extremely limited, but high-profile racer Mickey Thompson got the first two. One of those featured here is in the Factory Lightweight Collection.

Roger Huntington writing in Hi-Performance CARS is often credited with first using “Swiss Cheese” to describe lightened Super-Duty Pontiacs. It came to him after he counted 120 holes drilled in the perimeter frame of Royal Pontiac’s Catalina, driven by Jim Wangers. A total of 18 aluminum body parts were used to reduce the weight of a Super-Duty 421 Pontiac. A lightweight Catalina weighed approximately 3,300 pounds. Plexiglas side windows and aluminum deck lids helped keep the weight down. Some early cars ran with stock aluminum hoods fitted with Ford Super-Duty truck scoops!

For 1963, the SD-421 drag racing engine was improved considerably. Head castings were modified with taller intake ports, oval-shaped exhaust ports and fitted with larger 2.02-inch intake and 1.76-inch exhaust valves. New forged aluminum pistons raised the compression ratio from 11 to 12.5-to-l. Factory listing for the Group 35 Super-Duty 421 cars shows the B-W T-85 three-speed as standard and B-W T-10 four-speed optional.

Pontiac’s Malcolm “Mac” McKellar came up with a new cam and dual valve springs that allowed shift points as high as 6,400 rpm. Tuned aluminum exhaust headers, just 27 pounds per set, were mated to a single muffler system. While Pontiac upped the 421’s horsepower from 405 to 410, the new heads, camshaft, valve train and compression increase translated into a solid 40-50 horsepower bump. Racers experimented with a variety of cams, including Number 10 and 12 McKellar grinds.

Early in 1963, Royal Pontiac’s B/FX Lightweight tuned by Frank Rediker and driven by Jim Wangers, posted times in the low-12s at 117-119 mph. Wangers went on to a class win at the NHRA Indy Nationals. Howard Maselles later drove the Packer Pontiac lightweight into the NHRA record books, setting the C/Stock record at 114.64 mph in 12.27 seconds.

Total production of 1963 SD-421 Pontiacs is pegged at 88. This includes 14 lightweight full-size models and 12 Tempest compacts, plus steel-body cars and development vehicles.

While it is hard to deny the performance of lightweight Pontiacs or the romance attached to factory lightweight cars, the decision to drill-out the chassis was questionable. Lightening the chassis resulted in a lack of structural integrity that affected safe, reliable performance. They had to be braced and, in many cases, replaced. In retrospect it was not a smart decision. Pontiac’s Super-Duty racing programs were officially shut down on January 24, 1963, a victim of GM’s racing ban. It was the end of the road for the Bunkie Knudsen programs that had successfully reversed Pontiac’s early-1950s stodgy image. But, all was not lost. Less than one year later, Pontiac would jump-start the Supercar revolution with a car called the GTO!

Full coverage of Super-Duty Pontiacs are covered in DAY ONE, a new book by Chronicles Editor, Marty Schorr,https://www.amazon.com/Day-One-Automotive-Journalists-Muscle-Car/dp/0760352364/ref=sr_1_fkmr0_1?s=books&ie=UTF8&qid=1498587171&sr=1-1-fkmr0&keywords=DAY+ONE%2C+automotive+journalist+musclecar+memoir

 

 

 

 

 

 

3 thoughts on “’63 PONTIAC SD-421: SWISS CHEESE LITE!

  1. Were the single 4bbl units listed as 545012 the vehicles produced with the Nascar trapdoor manifold setup? And the 545024 the Bathtub manifold cars? Thank for the help and clarification

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