Pontiac GTO

Introduction

Pontiac chief engineer John DeLorean is often considered to be the instigator of the muscle-car craze, by taking an average sedan and endowing it with a big 389ci V8. Aside from the brakes (which were horribly inadequate), the original GTO featured plenty of performance enhancements that would soon turn it into a muscle car legend.

In a year or two every car company had followed suit, but none were able to match the combination of the style, performance, and mystique of the GTO. In its relatively short (11 model year) lifespan, the GTO managed to change its shape almost every model year. As a result, there's a GTO for all tastes.

As for those three letters, GTO stands literally for (in Italian) Gran Turismo Omologato or Homologated Grand Touring. It was a reference to a European racing vehicles. At the time Pontiac had a trend of naming their vehicles in this manner: Bonneville, Grand Prix, and LeMans were all from that era.

The 1964 model started out as a $300 performance option Le Mans. Using Pontiac's 389ci 6.40 litre V8, it was fitted with a 4 barrel carburettor making the engine good for some 325bhp (242kw). You could even option a "Tri-Power" version, with three two-barrel carburettors to 348bhp (260kW).

The stylists soon got to work on the front of the GTO, and for 1965 introduced the familiar stacked headlights configuration. The fake hood scoops could be turned -air induction setup. Not surprisingly, power was increased to 360bhp (269kW) in Tri-Power form. By 1966 the GTO was afforded its own model series, no longer being based on the Tempest.

The car was again restyled, the rear quarter panels gaining a distinctive late '60's "coke bottle" hump while the front end continued the evolution of Pontiac's signature stacked headlight styling. On the down side, GM brought down a corporate edict in mid 1966 effectively shelving any use of multiple carburetion - the only exception being the Corvette. To compensate for the resultant loss of power, the engineers increased the engines capacity to 400ci (6.60 litres) and a HO version which matched the previous Tri-Power equipped engines ratings.

The 1968 A-Body GTO and Motor Trends "Car of the Year"

In 1968 the GTO was again given an all new body, this time based on GM's new "A-body" platform. Heavier than previous versions, the engineers opted for an "Endura Bumper", the front bumper integrating with the front grille surround so as to make it almost appear as if there were no front bumper at all. Although an option, most wanted the hide-away the car a more aggressive and streamlined appearance. The '68 version would go on to win Motor Trend Magazines prestigious "Car of the Year" award.

Pontiac's GTO was the leader of the super cars. By 1967 it may have trailed Chev's SS 396 in sales, making it only No. 2, but it was the others who are trying harder. In image, performance and class, the "Tiger" was the car to equal. The '68 breed of cat was highly improved over the 1967 - which made a tough act to follow - in terms of style, body and innovations. The new Endura front bumper was the most significant and appealing innovation. It was formed of a pliable synthetic compound backed with steel. In most impact cases the bumper yielded with the force and sprung back to shape when the force was withdrawn. It also served as a snubber in low speed impacts by helping to bounce the car away from the object, giving real meaning to the word bumper. It is the same color as the car and resists knicks and chipping better than sheetmetal. We observed a GTO bumper which had been in a mishap while driven by a Pontiac employee. It was a strong impact and caused some metal wrinkling. The car was back on the road an hour and a half later with repairs given only to the metal, and none needed for the bumper.

Performance

Four engines were offered for the 1968 GTO. All were 400-cu.-in. displacement V8s, with single unit carburetion and hydraulic lifters. The standard engine was a 350-hp version, with torque rated at 445 lbs.-ft. A single 4-bbl. Rochester carb was used, and compression was 10.75:1. This engine could be mated to either the standard 3-speed manual transmission, or optional 4-speed floor shifted gearbox. The 3-speed Turbo Hydra-Matic was also optional. Standard rear axle ratio was 3.55:1, and 3.23:1 was supplied with air-conditioning. The optional ratio was 3.36:1. An interesting engine offered for all GTOs was the regular fuel, 265-hp V8, which used a 2-bbl. carburettor. It had a mere 8.6:1 compression ratio, but developed 397 lbs.-ft. of torque from the 400-cu.-in. V-8.

The camshaft was quite a bit tamer than the standard GTO engine, but if performance on a big scale wasn't the strongest point for the person interested in a "super car," the way it used the vast reserves of torque made it a brilliant highway cruiser. Better still, at the time in the USA it made it less expensive both at the browser and for insurance. It was only offered only with Turbo Hydra-Matic and came with a 2.93:1 axle ratio. Optional gears were 2.56:1, 3.23:1, plus the 2.78:1 with air-conditioning.

Another engine option was the H.O. (high output) 360-hp V8. using only a single 4-bbl. carb, but developing both its torque rating of 445 lbs.-ft. and higher hp at a greater engine speed. Prime difference here was the cam, but only the H.O. engine mated with manual transmission used the hotter cam. When hooked to a Turbo Hydra-Matic, the standard engine cam was used, but this engine did use a different series carburettor than the standard motor for part of its higher output. The H.O. 400 could be had with standard 3-speed or optional 4-speed manual gearboxes, or Turbo Hydra-Matic. Standard rear axle ratio was 3.55:1, with 3.23:1 supplied with air-conditioning.

Top of the tree for the GTOs was Pontiac's Ram-Air 360-hp stormer. Horsepower was rated at 5400 rpm, 300 higher than on the H.O., and the identical torque rating was also found at a higher speed: 3800 rpm vs. 3600. The "Ram-Air" term was derived from the fresh air intake carburetion which utilised functional hood scoops to feed outside air to the carbs. A foam rubber lipped pan shrouded the carb opening, with the lip fitting flush to the hood's underside.

This effectively kept warm engine compartment air from feeding the carburettor. The Ram-Air V8 had a much hotter cam than the H.O., with 301-degree and 303-degree duration on intake and exhaust valves respectively, compared to the H.O.'s 288- and 302-degree readings. The somewhat milder H.O. 400 cam was used in Ram-Air cars with automatic transmissions, but torque and hp ratings were identical to stick shift cars.

Only a 4.33:1 rear axle gear was available for Ram-Air cars. Air-conditioning was not available. This was definitely not a street-driving gear, and it is claimed by some web sites and Pontiac blogs that there were a few US based dealers hesitant to sell Ram-Air cars if street driving was to be the only function. We are not sure if these claims are true, given the highly competitive nature of car sales, however if some dealers did at least try to persuade buyers away from the high end engine we really cannot understand why. After speaking to a few owners, they will tell you that the Ram-Air was not all that hard to live with, but the outside air feed and low mileage required the patience and care of a true performance fancier. Only the optional 4-speed manual or 3-speed automatic were available for Ram-Air GTOs.

Handling, Steering & Stopping

The GTO handled like a flat rock on water, and that is a compliment. The GTO was a highly "understanding" car with good tractability, stiff but quick rebound, and was highly predictable. The car wasn't meant to be tortured on a track in stock form, but would take a large amount without complaint. The high spring rates (310 pounds per inch front; 122 rear) and G70 x 14 wide-pattern tyres which effectively secured the car under hard usage, also made it - overall - one of the most pleasant touring vehicles of the 1960s. Steering was average by the standards of the day, meaning there was understeer in a hard, briskly driven corner, but you could regain neutral conditions by judicious use of the accelerator.

The power-steering unit had 17.5:1 gear ratio and took 4.2 turns of the wheel to go from lock-to-lock. The manual steering versions took 5.6 turns of the 15.25-inch diameter wheel to go from lock-to-lock, and the gear ratio was 24:1. We doubt very few GTOs hit the streets without power steering, and suspect those that were not fitted were soon converted. The front disc/rear drum power-assisted brakes were class leading – and by that we mean they were the best available on any American Muscle Car from the 1960s – leastwise as was available from the showroom floor. Road testers from the time recorded braking from 60 mph in 145 feet – perhaps not the shortest distance then being boasted by Detroit – but the Pontiac would do it without fade, and without variation from a straight line and a minimum of lockup. Pedal effort was slight and, in an era long before ABS, the power assist didn’t fully take over the system.

Comfort, Convenience & Ride

Comfort abounded in the GTO. It had all the qualities of Pontiac's Grand Prix, but in a smaller package. Nothing was out of reach of the driver. Back seat passengers didn't have it quite as good as front ones in the leg room department, but the seats were no less comfortable. At the time, all GM "A" (intermediate) body cars had vent-window crank handles for 1968, and they were brilliant in operation. Another small convenience factor which young buyers with small children would have welcomed was the optional collapsible spare, which added an additional half cubic foot more boot space than was possible with conventional spares. With the car being six inches shorter for 1968 - taken from the rear deck - you can appreciate why the use of a collapsible spare was so important to American buyers, who were used to cavernous dimensions inside the boot.

The 1968 GTO came with a Hurst linkage. The main feature was a dual-gate automatic shifter on the console – much like what is found on atmo cars today. One side required only pushing the lever the desired direction to change gears, while you could also simply select full Auto and let the box do all the thinking. The 4-speed operated as smooth as a politician at pre-election time. Throws were close and short, and there was no "hang-up" between gears. A new feature on the ’68 models was a "key-in" buzzer . When the driver's door was opened with the key left in the turned-off ignition, the buzzer would sound. The Japanese would soon catch on to this idea and introduce it onto their much cheaper 4 pot models.

Behind the wheel the GTO was one of the most pleasant over-the-road cars then going. Ride was firm, but choppiness on undulating surfaces didn't present itself, and the stiff suspension did much in eliminating tail sag with a load of people or baggage. The best way to appreciate the ride was to take a short spin in a "plush-mobile" sedan with bed-spring suspension. Then, after tooling the GTO a while, a driver became aware of a trait known as "control." No wallowing in dips, no excessive diving and squat and quick steering response.

The 1969 GTO and The Judge

Arguably the best iteration was to come in 1969 with the release of "The Judge", which featured among other things a popular-for-the-time bright paint scheme and even more powerful engine. Optional on both regular and Judge models was the Ram Air IV air induction system, said by the factory to deliver 370bhp (275kW). Today you would rarely hear a car manufacturer under-quote the power output of their engines, but this was the case with Pontiac. At the time, insurance companies were starting to take a dim view of the growing muscle car genre, and premiums were putting the vehicles out of the reach of many buyers. Strangely, every time a motoring journal tested a "Judge", they would find the engine delivering a staggering 415bhp (305kW). Still, the official figures were stated as 370bhp, a good 40bhp under the reality.

The 1970’s models were again restyled, now featuring four exposed round headlamps and a narrow grille, as well as a body-side crease and restyled rear. A 455ci 7.50 litre engine was added to the range – Pontiac claiming the engine good for 360bhp (264kW), but the game was up, and everyone knew the wilder-beast was actually good for a whopping 420bhp (309kW). Insurance premiums and the oil scare of the early 1970’s would take it’s toll at the showroom, and the luster started to fade as stricter emission controls started to “genuinely” reduce power output.

By 1972 the GTO had once again become just an “option” package, based on the compact Pontiac Ventura. Many purists dubbed the car “A Chevy Nova in drag”, which was perhaps a bit harsh, but the latest iteration was in fact only a shadow of the car from the 1960’s. 1974 would see the passing of the GTO, although 25 years later GM would import the wonderful Monaro coupe and re-badge it as a GTO re-kindling the spark – but that is another story. In the halcyon days of the mid to late 1960’s, the GTO sold in great numbers and would fuel the competition between GM, Ford, and Chrysler that would keep the muscle car industry thriving for years to come.