Every V8 Engine That Powered The Pontiac GTO – Jalopnik

In some circles, “GTO” is synonymous with huge V8 energy. When that GTO badge first landed, it wasn’t to designate a mannequin, however slightly an possibility bundle. And even so, one of many non-negotiable performance-focused upgrades that got here with the GTO bundle was the 389 V8 we will cowl in a second. This is a automobile that has been out and in of the combo for a lot of muscle-car historical past, and the story of the GTO’s powerplants typically mirrors the story of the American auto business via these a few years. You bought the mid-’60s pleasure with the identify’s debut, Malaise Era frustration with the comparatively tepid 350, and the LS1 and LS2’s return to kind, which might change into among the many final gasps of Pontiac itself.

All advised, you begin with 4 Pontiac-built V8s. Then, after a 30-year hiatus, the GTO returned within the type of an Australian-built coupe with an LS below the hood. So you’ve got bought the early ones, the lacking ones, the late ones, and even one which bought away — a Super Duty 455 that did not fairly make it to showrooms however did land in magazines. With such a roller-coaster historical past, it is no marvel that what began as fake racing branding turned one of the vital enduring combos of three letters in automobile historical past.

For 1964, Pontiac’s Tempest LeMans was accessible with an possibility bundle that had by no means been provided earlier than. It marked the very starting of the GTO identify and arguably the start of muscle vehicles themselves. This wasn’t the primary implementation of the 389 V8, however it was the primary time Pontiac had dropped it into one in every of its smaller, lighter vehicles, delivering what is likely to be described as a proof of idea for the muscle-car components itself.

The present 389 had a four-barrel carburetor that helped ship the motor’s factory-rated 325 horsepower. It was fairly a place to begin, particularly by Sixties energy requirements. There was additionally a 348-horsepower Tri-Power model with a distinct carb setup: three Rochester two-barrels. Buyers have been into it, and the components was established. But Pontiac did not cease there. For the second mannequin yr, each variations bought extra energy, with the Tri-Power reaching 360 horsepower. In-period testing put its 0-to-60 time at 5.8 seconds with 1 / 4 mile of 14.5.

Things have been evolving rapidly. For 1966, the GTO joined the ranks of vehicles that weren’t meant to be full fashions by turning into precisely that. The GTO correct was born. That last yr for the 389 additionally introduced the primary factory-installed “Ram Air” bundle.

The segment-defining 389 ran till 1967, when the 400 changed it. This time, consumers might select from a number of variations on the theme, with the total lineup together with a 255-horsepower two-barrel, a 335-horsepower four-barrel, and two choices at 360 horsepower apiece. The distinction between the 2 revolved round whether or not you wished Pontiac’s “Ram Air” consumption setup. This compelled consumers to decide on between two alternative ways to get to the identical horsepower quantity, with the powerband and the driving expertise various relying on which was chosen.

Pontiac’s Ram Air program turned the centerpiece of the 400’s continued evolution. The 400’s extra critical efficiency variants finally acquired round-port heads. The first was 1968’s Ram Air II, whereas the Ram Air IV carried a revised model of the design into 1969 and 1970. By 1970, the usual 400 made 350 horsepower, whereas the Ram Air III and Ram Air IV carried rankings of 366 and 370 horsepower, respectively. The Ram Air IV additionally produced 445 pound-feet of torque, making it the highest-rated manufacturing 400 provided within the GTO.

“Mainstay” matches as a result of the 400 wasn’t merely one step between the 389 and the 455. It remained the GTO’s commonplace engine after the bigger 455 arrived, and the Ram Air 400s truly carried greater marketed horsepower rankings than that authentic 455. The 400 lasted via 1973, when the bottom model was rated at 230 web horsepower and 325 lb-ft of torque. Its seven-year tenure lined each the height of Pontiac’s horsepower struggle and far of the retreat that adopted.

Trouble was brewing for automobile lovers in America, even when they hadn’t but realized the influence. The regulatory shifts that might usher within the Malaise Era had began to coalesce, however not earlier than Pontiac snuck in below the wire with the 1970 GTO, along with an accessible 455 that was taking the automobile in exactly the other way from the place it, and the business, would finally be pulled. With 360 horsepower and 500 lb-ft of torque, the brand new motor delivered 10 fewer horsepower than the Ram Air IV 400, however with a further 55 lb-ft of torque.

That proved to be the 455’s high-water mark, at the very least on paper. As emissions requirements went up and lead in gasoline went down, output suffered. The “High Output” 455 within the GTO now sat at 335 gross horsepower and 480 lb-ft of torque. Those have been nonetheless critical numbers, however this new trajectory was definitely a bitter tablet to swallow. Under a brand new energy score system in 1972, the ultimate 455 H.O. delivered 300 horsepower and 415 lb-ft of torque. Those unfazed by malaise might lean into the vibe even more durable with the much less aggressive D-port 455, which produced 250 horsepower and 370 lb-ft of torque. Regulations had arrived, the worst period of automobile design was afoot, and you will discover that the following entry on this listing begins with a 3.

For 1974, displacement wasn’t the one space the place it felt like Pontiac was transferring backward via time. The GTO identify had as soon as once more turn into an possibility bundle, and now Pontiac moved it from the midsize LeMans to the smaller Ventura, a Pontiac mannequin listed among the many vehicles that almost all shocked Jalopnik readers with their horrible drive high quality. There was one engine accessible this time: a 350-cubic-inch V8 that served up all of 200 horsepower. It felt just like the writing was on the wall for the tip of the GTO, and it was.

To be truthful, although, the efficiency was much less anemic than the specs steered. A Cars journal comparability pitted the ’74 GTO towards the debut ’64 and produced surprisingly related outcomes. The older automobile reached 60 mph in 7.4 seconds, whereas the newer one bought there in 7.7. It’s not precisely the end result you need after a decade of progress and innovation, in fact, however not fully embarrassing, both. In any case, this was the tip, at the very least for some time. Pontiac constructed simply over 7,000 vehicles with “GTO” written on them in 1974 after which shelved the identify for 30 years.

Three a long time after the unique GTO disappeared, Pontiac headed to the opposite aspect of the planet to discover a approach to deliver it again. The Holden Monaro was an Australian-built, rear-wheel-drive coupe with 4 seats, an unbiased rear suspension, and sufficient room below the hood for GM’s LS1 V8.

The ensuing 2004 GTO did not actually resemble its predecessors and, simply to be clear, by that we imply it did not look nice. But because of the 5.7-liter from Chevy, Pontiac was again in enterprise so far as efficiency went, with the LS1 producing 350 horsepower and 365 lb-ft of torque, and an non-compulsory six-speed Tremec handbook. Buyers bought a Corvette motor for Pontiac cash and efficiency that may not have been on par with the ‘Vette, however worthy of the GTO badge nonetheless. The six-speed went from 0 to 60 in 5.3 seconds and did the quarter-mile in 14 seconds flat. It was a surprisingly credible bundle dynamically, made all of the stranger by being wrapped up as a really normal-looking coupe.

Proving the upside of cross-brand parts-bin sharing as much as and together with whole-ass engines, GM’s improve from the LS1 to the LS2 benefited the GTO virtually instantly. In 2005, because of the brand new 6.0-liter V8 from Chevy, output climbed to 400 horsepower and 400 lb-ft of torque. This amounted to an additional 50 horses and 35 lb-ft after one mannequin yr again within the sport because the automobile was simply starting to shed its Australian accent.

As a end result, the 2005 Pontiac GTO was the final word sleeper within the mid-2000s, with the six-speed handbook able to attending to 60 mph in 4.8 seconds and reaching a quarter-mile time of 13.3 seconds. It was not solely quicker than the LS1 model but in addition traded blows with the then-all-new Mustang GT and got here out forward in most efficiency classes, at the very least by the evaluation of Car and Driver on the time.

Pontiac saved the music going into 2006 with the identical engine, however that turned the GTO’s last mannequin yr (once more) because the Holden Monaro ended its personal manufacturing run. Soon sufficient, the defunct nameplate can be adopted by Pontiac itself, maybe saving the GTO the indignity of being resurrected as some type of hybrid crossover 20 years later.

The promising-sounding Super Duty 455 was taken from this world earlier than it had an opportunity to make it right into a manufacturing GTO, which is how a Pontiac muscle automobile that did not get made turned Performance Car of the Year.

The Super Duty was introduced forward of the 1973 mannequin yr, with Pontiac promising a correct race motor dialed again simply sufficient to make it appropriate for street use. The Super Duty bought a bolstered four-bolt primary block, cast rods and pistons, improved oiling, reworked round-port heads, and a higher-capacity consumption and exhaust. The preproduction GTO was rated at 310 horsepower, whereas the emissions-certified one that might finally land in manufacturing Firebirds had 290 web horsepower and 395 lb-ft of torque. 

Car journalists who drove the GTO misplaced their minds over it. Which is nice. Because they’re the one ones who ever bought their palms on it. As Hemmings remembers for us, Hi-Performance Cars journal put the ’73-GTO-that-wasn’t via its paces and went as far as to declare it “Car of the Year.” Between the time the article was written and the time it went to print, the tide turned at General Motors. The firm pivoted to give attention to security and gas economic system and left a few of its efficiency priorities, together with the automobile of the yr, within the mud. The Super Duty 455 GTO was carried out. It was clearly an ideal automobile, however the car-buying public by no means bought to search out out.