GM’s mid-size A-body platform was extremely successful in the 1960s and early-1970s. Ford and Chrysler with their mid-size offerings just couldn’t seem to match the sales of GM’s extremely popular A-bodies. During this era the A-body platform seemed to be the perfect size not too big like GM’s behemoth B-body and C-body offerings or too small like GM’s rear-wheel drive X-body platform. In other words the A-body seemed to fit very well with the needs of many buyers. The only problem with success is that it’s all too easy to make changes that offend the buyers which leads to dropped sales as a result.

This was the pickle that GM found itself in, most automakers in this position would have taken the conservative route – the path of gradual change. GM thought differently, it released the radical Colonnade styled A-bodies for 1973. It was a big gamble since the overall styling of the Colonnade A-body was futuristic, streamlined, and just plain wild in comparison to the overall styling of the 1972 A-body. Also not helping was the Colonnade was larger and heavier than the A-body platform it replaced which would put GM at an efficiency disadvantage after the 1973 Oil Crises which had gas prices soaring.

One big advantage of the Colonnade A-body was it was the perfect platform for the GM’s A-body based muscle cars. With expansive space under the front hood, even the biggest of V8s easily fit. The fastback styling of the 2-door Colonnade A-body fit the "muscle car" image perfectly. And the Colonnade’s stiffer chassis made better handling much easier to obtain. GM which eliminated all its division high compression high performance V8s for the 1971 model year seemed to have no problems with forging ahead with performance oriented big cubic inch low compression ratio V8 offerings. Upon the release of the Colonnade A-body GM had envisioned its A-body muscle cars would be standard with 350 CID V8s and larger displacement V8s would be optional. They didn’t anticipate the skyrocketing fuel costs during the 1970s decade and the future arrival of the EPA’s Corporate Average Fuel Economy (CAFE) standards. They were only anticipating tighter emissions standards a few years down the road when the 1973 model year started.

1973 which seemed like a bright year for GM muscle cars at its start, turned out to be a last big party which few buyers attended. GM had sliding muscle car sales since 1970 and it had hoped that 1973 would be the year they bounced back. Unfortunately that wasn’t to be. The Colonnade platform was very successful but the success couldn’t stop the death of the A-body muscle car. Here’s a breakdown of the GM’s 1973 A-body muscle cars.

1973 Buick Gran Sport

Even in 1973 Buick was trying very hard to keep alive the spirit of the original muscle car era A-body.  Buick which had replaced the "GS" moniker with the original "Gran Sport" as used on Buick’s first muscle car, still was acting as if the original muscle car era had not ended.  It offered four different engine options for the 1973 Gran Sport from very mild to wild.

 

Standard on the Gran Sport was a 175 net horsepower 2-bbl 350 CID V8. Unlike the other motors available for the Gran Sport for 1973 which had dual exhausts, the 2-bbl 350 V8 was mandatory with single exhaust. A 190 net horsepower 4-bbl 350 was optional. Next up the performance ladder was a 225 net horsepower 455 CID V8. And last was the big performance kahuna which was the Stage 1 455 CID V8. It may have been slightly detuned compared with the first 1970 Stage 1 455, but it could still cut the muster. In fact so well that barring Pontiac’s Super Duty 455 CID V8 and Oldsmobile’s L77 455 CID V8, it was the hottest high-performance V8 available for 1973. All engines were available with either a 3-speed automatic or a 4-speed manual transmission. A 1973 Grand Sport when equipped with the Stage 1 455 and a 4-speed manual was capable of of low-14 second 1/4 mile times which was lightning fast for 1973 and was slightly less than 1 second slower than the legendary Stage 1 455 which was available in the 1970 Buick GS and GSX. To fully understand how the Stage 1 even in 1973 was still harnessing great power – 270 net horsepower which was the equivalent of 340 to 350 gross horsepower, a range that during the apex of the muscle car era was considered a lot of horsepower.        

With the many engine options offered and the Gran Sport’s fantastic looks – the Gran Sport subjectively had the best styling of the 1973 Colonnades. The Gran Sport had the most attractive front end styling that meshed well with the rest of the car. With a total production of only 6637 units, the great styling didn’t translate into strong sales even when Buick sold just a hair under 300,000 A-bodies for 1973. The Gran Sport returned for an encore presentation for 1974, for 1975 the Gran Sport moved to the smaller Buick Apollo (X-body) platform for only one year. After 1975, the Gran Sport was gone forever.   

1973 Chevrolet Chevelle SS

The Chevelle SS since its 1965 inception had been one of the most popular muscle cars on the scene. By 1970, the Chevelle SS had obtained legendary status by offering the optional 450 gross horsepower LS6 4-bbl 454 CID V8. It had the highest factory horsepower rating of any muscle car during the golden era.  For 1973 the 4-bbl 454 V8 was still optional but it was now rated at 245 net horsepower. Which on the surface seemed to be almost half of the mighty LS6, but in reality it wasn’t a fair comparison. The LS6 was measured in "gross" horsepower versus "net" with the later being a more stringent standard. Translated, the 245 horsepower of the 1973 454 was around 320-325 gross horsepower. Still well under the LS6’s gross horsepower rating but right on the money when compared to many 1960s muscle cars. For instance the 1966-1969 Chevelle SS with the base 4-bbl 396 CID V8 produced 325 horsepower, so in this type of light the 454 powered 1973 Chevelle SS was respectable. For the 454 powered 1973 Chevelle SS, it took around 7 seconds to go 0-60 mph and around 15 seconds for the 1/4 mile. This not only was respectable but was downright fast by 1973 standards. The 1973 Chevelle SS’s base motor was the 175 net horsepower 4-bbl 350 CID V8 – this was the equivalent of 220 gross horsepower placing it below par of most muscle cars during the golden era. Fortunately both the 350 and 454 V8s were offered with either a 4-speed manual or 3-speed automatic transmission.

 

The Colonnade styling gave the 1973 Chevelle SS a more modern sleek look that still looked all muscle car in overall appearance. High insurance rates had also taken a big bite out of muscle car sales, starting in 1970. Compared to other 1973 muscle cars, the Chevelle SS was a hot seller with 28,647 produced. Even though sales were good, Chevrolet decided to pull the plug on the Chevelle SS, it didn’t return for the 1974 model year.

1973 Oldsmobile Hurst/Olds

When most classic car fans think of the 1973-1977 Colonnade cars, the Oldsmobile Cutlass is normally the first car they think of. No small wonder, no GM division sold more Colonnade cars than Oldsmobile. The Cutlass was so popular it even was the best selling car in America multiple times during the 1970s and into the 1980s. 1976 was the first year the Cutlass earned the best selling car in America status. And the last year of the Colonnade Cutlass in 1977 got even better with a whopping 632,742 units for that year alone.   

Oldsmobile offered a 442 for 1973 and just like in previous years it was the high performance version of the Cutlass. The Colonnade styling worked so well for the 442, it was the most unique and distinctive looking Colonnade muscle car for 1973, it was by far the most wildest in styling. In previous years the GTO would have been the wildest styled of the bunch. Sales were decent with 9,797 442s produced for 1973. Oldsmobile with the 442 which offered different varieties of its 350 CID and 455 CID V8s including its top dog 270 net horsepower L77 455.

 

Even if the story ended there, Oldsmobile would have done its duty providing plenty of performance for 1973. Instead Oldsmobile took things one step further and offered the 1973 Hurst Olds which had a wild decal and paint scheme – black with gold stripes or white with gold stripes. There was a radical louvered hood scoop and other items to distinguish this serious performance car from its competition. From looking at the exterior, the Hurst/Olds looked the most fierce out of the Colonnade bunch for 1973.

The 1973 Hurst/Olds was the fifth car Hurst Performance and Oldsmobile had combined efforts on.  Oldsmobile would build what was essentially a white or black 442 which would be shipped for the final Hurst touches to Hurst’s Ferndale, Michigan facility.

And just like the previous Hurst/Olds since 1968, the 1973 was all performance. It was simple, all Hurst/Olds received a 455 CID V8. If a buyer ordered a 3-speed automatic transmission then the 250 net horsepower L76 455 was mandatory – this combo was known as the W-45 Hurst package. And if a 4-speed manual transmission was ordered the 270 net horsepower L77 455 was mandatory which was known as the W-46 (Hurst) package. Unfortunately only 9% of the 1,097 Hurst/Olds produced for 1973 were equipped with the L77 455 (W-46 package). Part of the reason was Olds performance buyers tended to be older and preferred automatic transmissions and air-conditioning, and with air-conditioning not being available with the L76 sales of the W-46 package were hindered.  What a pity, since the L77 equipped Hurst/Olds was good for low-14 second quarter mile times – extremely impressive for 1973. And when you consider that 270 net horsepower equaled around 340 to 350 gross horsepower during the golden era, it was easy to understand the L77 Hurst/Olds was packing quite a lot of punch.

Both the Hurst/Olds and the 442 would return again for 1974, and both nameplates would be available with a rear-wheel drive Cutlass platform on and off again for two more decades – the 1984 Hurst/Olds and 1987 442 would be the last of this kind.   

1973 Pontiac GTO

Only one phrase could describe the GTO offering for 1973 – "how the mighty have fallen". The once iconic GTO, the car that started the muscle car era in 1964 was now a shadow of itself. At the beginning of the 1973 model year it looked like the GTO was going to be the hottest American performance car, by the end it was merely an ample muscle car. Pontiac had anticipated offering the hot 310 horsepower Super Duty 455 CID V8 in the GTO. It had a preproduction test car it circulated to the press for review. This car was capable of mid-13 second 1/4 mile times. Hi-Performance Car magazine was so impressed with the test car that it awarded it "Car of the Year". Unfortunately Pontiac pulled a fast one and only offered the Super Duty 455 in the Trans Am and Firebird Formula that year, relegating the GTO to a standard 220 net horsepower 400 CID V8 or the optional 250 net horsepower 455 CID V8. Both motors were available with either a 4-speed manual or 3-speed automatic transmission. The 455 was the hot ticket for the 1973 GTO, even though it was not the Super Duty 455, it still managed a 14.77 1/4 mile time and 6.6 second 0-60 mph time which was nothing to balk at.

What hurt the most for GTO fans, was that it was quite clear starting in 1973 the GTO was no longer Pontiac’s favorite. The Trans Am and Firebird Formula obtaining the Super Duty V8 was only part of the story. The other part of the story was the GTO which had a body colored endura front-end ever since 1968 in order to offer the sleekest styling to its customers, was no longer available. Pontiac gave the fancy endura front-end treatment to the new 1973 Grand Am (also built on the A-body platform). The GTO was left with a big ordinary front chrome bumper. This was not to say that styling was bad, it just wasn’t as good as it could have been. The GTO looked like a base-level 2-door A-body with a "GTO" label affixed. The GTO did offer one nice standard item which was also available on the 1973 Grand Am – dual NACA air duct hood which unfortunately was non-functional and for decoration only.

 

The pedestrian nature of the GTO looks obviously hurt sales which dropped to 4,806 units – the lowest of the 1973 A-body muscle cars except for the limited production Hurst/Olds. Fortunately this would be the lowest sales output year for the GTO. Sales would rebound for 1974 when the GTO moved to the smaller X-body platform and was only equipped with a 350 CID V8. The rebound was not substantial enough, and the GTO would not return for 1975. For all practical purposes 1973 would be the GTO’s swan song before it went to the grave.

Written contents in this article – © 2014 Pete Dunton – All Rights Reserved