1973 SD-455 Trans Am - A Charmed Life

Sometimes automotive scribes have to beat themselves over the head to comprise a strong lead for a feature article. Other times one just comes to them as naturally as waking up in the morning. Then there's the case of Mark Norris' '73 SD-455 Trans Am. This story has so many possible powerful leads that it made my head swim.

Let me explain. First it's an SD one of 180 automatics of 252 total--instant hook right there right? Then there's the fact that this Bird actually has a column--shifted automatic transmission-in a T/A! If those weren't enough how about the fact that Mark bought this T/A in 1978 from the original owner, a friend, for $2,500? And today the Pontiac has yet to be restored but is slightly modified and is raced on a regular basis. Are you beginning to see my problem? So let's just start at the beginning and let the superlatives fall where they may.

On August 3, 1973, a salesman named Leonard at Ed Hammock Motors in Atlanta, Texas, prepared Car Invoice No. 6826 for the Trans Am that you see here. Very late in the sales season to be sure, but then again, all '73 SD Birds were sold late due to a belated introduction of the option. By the time the price, the options, and the tax, license and title were totaled, the purchaser, a Mr. Leslie Hagin paid $5,309.88 for an incredibly rare SD-455 Trans Am.

Meanwhile, just a few miles from the dealer lived Mark Norris, a 16 year-old car nut who was smart enough to know a desirable Pontiac when he saw one cruising around town. As luck would have it, a few years after Leslie bought the T/A, he and Mark would end up working at the same company. They became fast friends due to their shared interest in fast Pontiacs, and Norris, who had bought a '75 T/A new and got rid of it in favor of a '70 T/A because it was faster, kept constant tabs on the rare '73. In 1978 bad news for the owner provided Mark with the opportunity of a lifetime--the SD had spun a rod bearing and Hagin was looking to get out. For $2,500, Norris at just 21-years old was the proud owner of a piece of musclecar history.

He soon rebuilt the SD-455 engine and Mark has cared for the Pontiac like the rarity that it is ever since. "I constantly pay attention to keeping up with maintenance and repairs. I want to preserve it rather than perform a full-blown restoration on it," he explains. To that end, in the ensuing years POR-15 was applied to the chassis to keep rust at bay and a new carpet was installed, though the rest of the black Morrokide interior (code 236) is original. In 1992, the T/A was repainted Cameo White (GM code 11 or C) using single-stage Sherwin Williams Polyurethane by Texas-T Paint and Body in Atlanta. Since then, Mr. Bill's Paint and Body, also Atlanta based, has handled touch-ups as needed. But that's not the end of the story. This '73 is no pampered trailer queen. Mark has also raced the SD...a lot!

From the late '70s to present, Norris and his Pontiac have racked up wins on the street and in heads-up competition at the Original Musclecar Nats. It was an NMCA class record holder in H-Stock and was a class winner at the Pontiac Southern Nats in 1999 and a runner up in 1998. Mark recalls, " Back then I went through the stages of modifying the Pontiac to match the rules. Now I just do what I want and enjoy it."

Since Trans Am and owner are so proficient at tripping the lights of the 1,320, HPP invited them to race during one of our Lone Star Pavement Pounder Shootouts and we photographed the T/A in action for this story.

For our shindig, Norris' Pontiac was set up thusly: The original XD-code block had been bored to 462 cubes, replacement .030 over TRW forged pistons wrapped in Sealed Power moly rings pumped in the cylinders via the stock crank and forged steel SD rods. Compression ratio was stock 8.4:1 as were the #16 heads with factory 2.11/1.77 valves. A deviation was the cam, which was a Ram Air IV replacement featuring 308/320 degrees advertised duration, 230/240 degrees duration at .050 with .520 lift using Ram Air IV 1.65:1 stamped steel rockers. And it was installed 2 degrees advanced.

The induction system appeared completely stock employing a factory 800-cfm Q-Jet (#7043270), the SD Delco points distributor (#1112218), and the LS2 cast-iron intake. Mark however, tuned the combination with .074 primary jets and "DA" or "DH" secondary rods in the carb, a distributor recurve to get the timing all in by 2,400 rpm, and by port matching the intake to the heads. He tried a few different exhaust systems over the years but found that the best combination for use with the factory cast-iron exhaust manifolds consisted of 2 1/2-inch head pipes (with a crossover) attached two a pair of Borla mufflers and 2 1/2-inch tailpipes.

Beneath the rockers the suspension is stock save coilover shocks in the rear. Mark has used some loose front shocks from time to time to race and he does loosen the front stabilizer bar bushings on the drag strip but the bars and good front shocks are retained for regular street duty.

Power is fed to the shift kit enhanced Turbo 400 (code PQ) via a 2,800 stall converter. And the twist is put to the pavement through a 3.42 Safe-T-Track rear (original gears were 3.08s that were changed by the original owner prior to Mark purchasing the SD) and M/T 26x8.5x15 slicks on Rally II wheels. Skinny 15x3.5 Cragars and M/T Front Runners pumped up to 40 psi keep the rolling resistance to a minimum up front. On the street, the race meats and wheels give way to Rally IIs and BFGs.

Curb weight is a stout 3,850 pounds thanks in part to the optional A/C, which adds 110 pounds while race weight is 4,050 pounds and Mark runs 89 octane in the tank. Regarding his launch technique, Norris shared his thoughts. "I heat the tires with a burnout, which is very important. At the line I just load the chassis, flashing the converter to 1,200-1,500 rpm and nail it on the last yellow. Shift points are 5,500-5,700 rpm and the T/A goes through the traps at 5,250 rpm."

With 12-15 psi in the M/Ts, the 60 foot is 1.78 and the T/A runs the quarter in 12.6 at 109.65 in good air and is then hauled to a stop with the factory disc/drum brakes. For our outing it was 100-plus degrees and the T/A was running 12.80s-12.90s for the day at 107 mph.

Having 30-years racing experience under his belt in everything from Pontiacs to Vipers and Shifter Karts, this soft spoken hospital pharmacist has made many memories with his T/A on the track and cruising the streets of Atlanta, and selling the Pontiac has never even been a consideration. "It's good to know that the very special cars, which we have hung onto from the "bad car times" have found their place in automotive historyand we are still out there driving them today!" Mark said. And now that we have wrapped up this exercise in choosing a proper lead for this proper Pontiac story, I'm off to take some Tylenol.