1973 Pontiac Trans Am - the Quintessential Tough Guy Car


The 1972 model year was a minor setback for the Trans Am in terms of production - with a paltry 1,286 total units. The main culprits were a crippling factory workers strike, and the white with a blue stripe and blue with a white stripe exterior coloring schemes which had run their course after a few model years of production. 1973 would be different, Pontiac would offer three distinctive colors - Buccaneer Red, Cameo White (a carryover from 1972), and Brewster Green. The 1970-1972 big full body racing stripe also bit the dust. Buyers responded well to the color scheme offerings and production rose to 4,550 units for the 1973 model year. This wasn't just a one year blip on the radar screen, but the sign of escalating sales that would make the Trans Am the hottest selling performance car in the world by the late-1970s.

While performance was dying on the vine by the 1973 model year, Pontiac was kicking up the heat with the Trans Am. By 1973, the Trans Am's direct competitors had dropped their large displacement V8 options. The Ford Mustang had a 266 horsepower 4-bbl 351 CID V8 as its hottest and largest displacement motor. The Dodge Challenger was stuck with a 240 horsepower 340 CID V8. And even the Trans Am's GM F-body performance brother, the Camaro  Z28, had a 245 horsepower (L82) 350 CID V8 (the Camaro SS was dropped for 1973). So you can imagine how appealing the 1973 Trans Am was to buyers with a standard 250 horsepower 455 CID V8 and an optional (advertised) 310 horsepower Super Duty 455 CID V8. The base 250 horsepower L75 455 V8 powered Trans Am may have had 16 horsepower less than the top dog Mustang equipped with the 266 horsepower CobraJet 351 (Cleveland) V8, but it had loads more torque. The Trans Am's L75 455 produced a maximum of 370 lb-ft of torque at a very low 2800 rpm versus the Mustang's Cobra Jet's 301 lb-ft of torque at a much higher 3600 rpm. The tons of low-end torque which was the foundation of all good golden era muscle cars, gave the L75 455 a big advantage over the Cobra Jet 351. This was good news for the Trans Am, however this didn't mean the Tran Am didn't feel a performance pinch. The pinch was felt by buyers of the base Trans Am, since horsepower was down by 50 horsepower over the previous year 455 HO V8 which produced 300 horsepower. The 455 HO was the Trans Am's only engine for 1971 and 1972. The 455 HO was a hot motor that propelled the heavy 1971-1972 Trans Am down the quarter-mile in 13.9 seconds.


To replace the 455 HO, Pontiac engine engineers had come up with a new super performance engine for the 1973 model year called the (LS2) Super Duty 455 (or SD-455 for short). The initial plan was to offer the SD-455 in the 1973 GTO, Firebird Formula, and Trans Am. As the 1973 model year commenced Pontiac was to about to debut the new SD-455, and then a management change within Pontiac caused the SD-455 to be cancelled at the last minute. In fact Hi-Performance Cars magazine (April 1973 issue), even awarded the SD-455 equipped 1973 GTO its prized Car of the Year award. Pontiac had passed around a production spec 1973 SD-455 GTO to members of the automobile press to test drive. When the SD-455 GTO never made it to production, Hi-Performance Cars magazine was left with egg on their face. The anticipation of the SD-455 had most performance car fans on the edge of their seats. Eventually late in the model year, Pontiac accepted orders for SD-455 equipped Trans Ams and Firebird Formulas when Pontiac upper management agreed to commence SD-455 production. It's unknown how many SD-455 Trans Am and Formula orders were turned down before 1973transam-6athe final acceptance period. Some persistent SD-455 Trans Am and Formula original owners reported submitting repeated orders until the final one was accepted. Even with this trouble the SD-455 Trans Am and Formula were worth the ordering headaches and long wait. After-all where else back in 1973 were you going to find an American performance car with an advertised 310 horsepower horsepower rating? And with performance like that available in the spoiler and air dam laden Trans Am, it was a winning combination. In case there were any babbling naysayers, Hot Rod magazine obtained a 13.54 second quarter-mile time at 104.3 mph with a SD-455 equipped Trans Am. This figure was earth shattering, not only was the SD-455 Trans Am about 2 seconds faster than its best competition in 1973, it could beat some of the best muscle cars produced during the muscle car golden era. Mid-13 second quarter-mile times were what the fastest legendary (425 horsepower) 426 Hemi powered Mopar muscle cars were capable of. Imagine the dark cloud over performance cars that started in 1972, every muscle car fan is watching horsepower and performance figures collapse and automakers retreating towards the hills for cover. Suddenly there was Pontiac who didn't seem to care and bucked the trend and released one of its most potent muscle cars two years after the original muscle car show was over. The most amazing aspect of this story was that the SD-455 was so powerful with just a 8.4:1 compression ratio. Pontiac engineers had to jump through hoops to get EPA certification for SD-455 production which was the other reason why it was introduced late in the model year. Never-the-less it was produced and 252 Trans Ams were so equipped (only 43 Firebird Formulas were equipped with the SD-455). Even though the 1973 SD-455 was produced in small numbers, it led the way for the SD-455 to carryover to the 1974 model year and sell in almost four times the numbers. And even though the price of admission in the the SD-455 Trans Am club was a steep $521 back in 1973, it was worth every penny. It was the fastest American performance car in 1973 and 1974.


So what made the SD-455 such a powerhouse motor? Quite simply Pontiac threw the best performance parts on a 4.15 inch bore and 4.21 inch stroke and 4-main bolt 455 V8 it could muster. Add to that a 800 cfm quadrajet 4-bbl carburetor. Many performance cars back in the early seventies and 1960s for that matter had 750 cfm 4-bbl setups at best. Also used were Pontiac's extremely free-flow round-port heads, Ram Air exhaust manifolds, and forged pistons. Pontiac had originally intended to use the Ram Air IV cam however couldn't get EPA certification of the SD-455 with this cam. So Pontiac at the last minute substituted the 1967 Ram Air 400 cam which allowed the SD-455 to get the EPA seal of approval but dropped horsepower on paper to 290 (who was Pontiac kidding even with the new stricter net horsepower ratings the 290 horsepower the SD-455 produced was more than the claimed 290 horsepower). The 1967 Ram Air 400 cam may have been slightly milder than the Ram Air IV cam, but it did have the added advantage of boosting the SD-455's torque rating up to 395 lb-ft. It is believed that the Hot Rod magazine tested SD-455 Trans Am was equipped with the Ram Air IV cam instead of the 1967 Ram Air 400 cam. In the real world the milder cam crippled the Trans Am by no more than a few 1/10s of a second on the quarter-mile versus the hotter cam still putting the 1973 SD-455 Trans Am in 13 second quarter-mile range territory. Where the SD-455 Trans Am dropped to low-14 second quarter-mile range was when it was equipped with both the automatic transmission and air-conditioning which gave it a mandatory 3.08 rear axle ratio. Both the 3-speed automatic without air-conditioning and the 4-speed manual transmission equipped SD-455 were standard with a performance oriented 3.42 rear axle ratio. Unfortunately the base L75 455 1973transam-1Trans Am was relegated to mandatory 3.08 rear gears. All Trans Ams for 1973 no matter what the rear gear ratio was came standard with a Safe-T-Track rear differential.  

For 1973 there was one bad turn of events for the Trans Am, due to new government mandated noise regulations, the shaker hood scoop for both the SD-455 and L75 455, was now closed with a permanent plate in place where the 1970-1972 Trans Am had a solenoid operated flap that opened up to allow cool air into the air filter assembly. On the shaker hood scoop the L75 had "455" callouts while the SD-455 Trans had "SD-455" callouts.

The 1973 Trans Am's exterior was a carryover from the previous year only real change was the pattern on the twin front grilles had been slightly modified. All the wild spoilers and wheel flares were 1973transam-7still present. However there was a new option that gave the Trans Am a whole new persona when RPO WW7 was selected on the order sheet - this was the infamous big hood bird decal. When WW7 was not ordered, instead a much smaller bird decal was found on top of the front beak directly in front of the hood (just like all 1970-1972 Trans Ams). Many people don't realize that the hood bird was optional since the majority of 1973 to 1981 Trans Ams rolled off the assembly line with this massive hood decal. Pre-1973, behind the scenes there was a battle between Bill Mitchell, head of GM styling and John Schinella head of Firebird styling. Schinella wanted to include the hood bird as a Trans Am option however Mitchell who thought the big decal detracted from the Trans Am's looks wanted no part of it. Schinella eventually was able 1973transam-4to convince Mitchell to offer it as an option for 1973, and the rest as they say was history. The hood bird is what most people identify with the Trans Am - it made the 1970s Trans Am into a cultural icon.

1973 was also the introduction of the Radial Tuned Suspension (RTS) which was a specially tuned suspension for radial tires. When RTS was ordered the Trans Am's standard F60-15 bias ply tires were replaced with GR70-15 radial tires. RTS gave the Trans Am a very smooth and quiet ride however it came at a slight handling handicap since the F60-15 bias ply tires provided far superior cornering. But that wasn't the worst of it, all RTS equipped 1973 Trans Ams had white walls on the GR70-15 tires versus the F60-15 bias ply tires which came with white lettering. Somebody at Pontiac wasn't thinking, what buyer in their right mind wanted white wall tires on a fierce looking Trans Am? Buyers who wanted a Firebird body style with white wall tires were more inclined to purchase a Firebird Esprit. Never-the-less there were even some SD-455 buyers who opted for RTS - boy I bet they were surprised when they picked up their brand new SD-455 from the dealer after it arrived. And I am sure that some of the maiden voyages home from Pontiac dealerships by surprised 1973 RTS buyers included a unplanned stop at the local tire store for a set of new 15-inch white lettering performance radial tires. This didn't stop RTS from becoming a popular option, radial tires were the way future and everyone wanted them. Even by the late-1970s when radial tires were standard on the Trans Am a "RTS" plaque still remained on the Trans Am's aluminum engine-turned dash. As performance radial tires improved, within a few years most people forgot about bias ply tires. And even today, many early-1970s Trans Am without RTS owners have radial tires instead of the period correct bias ply tires. In other words today, nobody is crying the blues about the death of bias ply tires. Irregardless with or without RTS, the Trans Am was one of the best handling cars you were going to find for sale in America back in 1973. And just like the previous two years 15x7 inch Rally II wheels with trim rings were standard while a set of 15x7 inch Honeycomb wheels were optional.

Not much had changed in the Trans Am's interior space for 1973 except for the introduction of more upscale looking seating surfaces. Even the base vinyl seats looked more upscale. Black, Saddle, and White were the three colors available on these base seats. There was the more upscale custom 1973transam-5interior trim package which consisted of attractive vinyl seating surfaces available in Beige, Black, Burgundy, Saddle, and White. And the upscale trim package could also be ordered with the same upscale seats in cloth - the only downside was Beige was the only color available when cloth was ordered.

There was no doubt that the Trans Am was the hot ticket for 1973, Pontiac by this time had gotten the memo that the muscle car era was over but had elected to throw it in the trash where the memo belonged. The SD-455 was the big dog on the street for the 1973 model year and even the hottest 1973 Corvette - the one equipped with the 270 horsepower 454 CID V8 couldn't touch the SD-455. 1973 would mark the end of Corvette hegemony during the rest of the 1970s - the Corvette would bow to the new top American performance car the Trans Am. Another trend was also taking root, the Trans Am was beginning its tenure in movies and TV shows. A Cameo White L75 1973 Trans Am had ample screen time in Clint Eastwood's classic film, Thunderbolt and Lightfoot (1974), with Jeff Bridges doing the fast driving on the big screen. When movie production ended, Eastwood kept the Trans Am as a regular driver for several years. And movie screen icon John Wayne who was the lead star in the commercially successful McQ (1974) movie was seen driving a L75 powered Brewster Green 1973 Trans Am sans the big WW7 hood bird decal. Wayne spent a lot of screen time behind the wheel of this Trans Am which was involved in a memorable car chase scene. Unfortunately the Brewster Green Trans Am didn't stay with Wayne since it was destroyed as part of the movie plot. Even in the early-1970s John Wayne who was known as "the Duke" and Clint Eastwood were both the quintessential big screen tough guys. There was no car that typified the ultimate tough guy image more than the Trans Am of this era, so it was fitting the Trans Am would be driven by both the Duke and Eastwood.

Written contents in this article - © 2013 Pete Dunton - All Rights Reserved