It started innocently enough with an ad on eBay for a 1963 Pontiac LeMans Tempest with just 3,165 miles. With no engine or transmission, at first glace it seemed like just another derelict parts car. The Tempest had been part of a deal that included a load of scrap. At one point, the car was destined for a trip to the crusher, but there wasn't enough room on the truck. Instead of junking the Tempest, the seller thought he might get $500 if he was lucky.
What he didn't realize when he placed the ad on eBay was this wasn't "just another old Tempest." In fact, what he had was the ultimate barn find--one of six 421 Super Duty aluminum front end Tempests built by Pontiac in 1963 for Super Stock and A/FX drag racing. Instead of ending up as a cube of steel, it was on its way to being reborn as an NHRA racing legend.
The "1963 Tempest" eBay listing was soon being emailed to hundreds of Pontiac and drag racing fans across the country. It didn't take long to determine from the serial number that it really was one of the six 421 SD Tempest lightweights. For years, it was listed as "Whereabouts Unknown" in Pete McCarthy's superb book, Pontiac Musclecar Performance 1955-1979. According to Pontiac records reprinted in McCarthy's book, the 421 SD Tempest had originally been shipped by Pontiac to Stan Antlocer, who campaigned the car in 1963, sponsored by Stan Long Pontiac in Detroit.
Pontiac's Super Duty racing program had begun in 1961, and picked up steam in 1962 with 179 421 Super Duty Catalinas and Grand Prixs produced. A handful were built at the factory with lightweight aluminum body panels, and even aluminum exhaust manifolds (which had a tendency to melt). Some of these cars went to established racers like Arnie Beswick, Mickey Thompson, Jim Wangers, Lloyd Cox, and other top Pontiac Super Stock racers.
For 1963, along with the fullsized models, Pontiac constructed a handful of specially modified Tempest coupes and wagons for S/S and A/FX competition. The heart of the package was the 421 Super Duty engine, grossly underrated at 405 horsepower at 5,600 and 425 lb-ft of twist at 4,400. The fire-breathing 421 Super Duty was the most powerful engine Pontiac had built to date, and was packed with their best racing technology learned from NASCAR and NHRA competition. The block was well beefed, with larger main bearing bores to accommodate the special forged "990" crank with large 3.25-inch main journals and four-bolt main bearing caps. A large-capacity oil pump was housed in a deep-well oil pan.
The heat-treated rods were fitted to Forge True aluminum alloy pistons with 12.0:1 compression (13.0:1 pistons were optional for 420 horsepower). Cylinder clearances were "loose" to allow for expansion at high-rpm operation. The iron Super Duty heads had streamlined ports, were fitted with 2.02-inch intake and 1.76-inch exhaust valves, and had shallow chambers with reliefs cut at the top of each cylinder bore for better breathing through the big intakes. The valves were tuliped and swirl polished to improve flow and reduce deposits. Dual valvesprings with titanium retainers were also part of the package. A "McKellar number 10" mechanical camshaft with 308/320 degrees and 0.445-inch lift was standard, bumping hardened 5/16-inch pushrods and 1.65:1 rockers.
This 1963 SD Tempest was delivered to George DeLorean and was never modified. Like all six
The centerpiece of the Super Duty engine was the remarkable two-piece, cast-aluminum "Bathtub" tunnel ram intake designed specifically for the '63 421 Super Duty. Pontiac historian Pete McCarthy has even called the bathtub intake "the best factory-developed manifold in existence, regardless of make." The manifold consisted of two groups of four passages that form 11-inch ram tubes that opened into the bottom of the plenum chamber. The size of the plenum and the length and diameter of the tubes were balanced to prevent them from pulsating through the carburetors and to maximize velocity. Pontiac Engineering recommended that the Super Duty had to idle over 1,000 rpm to ensure that the bearings and valves received adequate lubrication.
The 421 SD fit nicely in the engine bay since it had the same exterior dimensions as the Tempest's optional 326ci engine; however, the installation required special exhaust manifolds. These welded steel tri-Y exhaust manifolds had a single three-bolt outlet to side-exit collectors that ended in three-inch Lake-style "dumps" covered by a plate. When the covers were removed, an unobstructed flow from the headers was scavenged. When the cover plates were on, the exhaust was directed from a balance pipe through a 2.25-inch exhaust pipe to a low-restriction, reverse-flow muffler, and then out a 2-inch-diameter tailpipe.
Pontiac chose to equip the cars with a four-speed version of their Tempest rear transaxle, called Powershift. All were equipped with 3.90:1 limited-slip rears. Each SD Tempest was painted Cameo White and fitted with 326 emblems in the grille. All 421 SD Tempests received aluminum front ends. They were delivered with 10-inch M&H Racemasters at the rear on bare, black-painted steel wheels. Inside was a blue bucket seat interior with the gear selector located between the front seats.
This is the original aluminum hood from Antlocer's SD Tempest. No one is sure when it was
Of the six SD Tempests, Antlocer's is unique, thanks to the conversion work he did to the drivetrain. "I was notified to pick the car up at the factory the first week of February 1963," Antlocer told Popular Hot Rodding. "I drove the car from the factory to the shop, and we pulled the motor. We balanced and blueprinted it, and got the rest of the car race ready."
The first tests at Detroit Dragway were disappointing. "I made at least a half-dozen runs," Antlocer said, "and it just wasn't there. The car just wouldn't e.t. like we thought it should with the big 405hp motor in it. It wouldn't mile per hour that great, either. We brought the car back to the shop and talked about what to do. We thought we ought to put a fullsized Pontiac rear end in it like Mickey Thompson did with his '62 Tempest."
"I called Bill Klinger at the factory," Antlocer said. "He was our engineering liaison. I asked him if it would be possible to put a big Pontiac rear in the Tempest." Klinger said that was fine, and asked Antlocer for a list of the parts. "He said Pontiac would assign part numbers on them and submit them to the NHRA," Antlocer said, "and then the car would be legal."
With help from Ted Henke, they pulled the transaxle out and set a '57 Pontiac rearend in the car, and measured it out for use with both7- and 10-inch tires. They took the rear end to Logghe Brothers in Detroit and had them cut the rearend down. "We used the '57 Pontiac leaf springs and had shackles made for them," Antlocer said.