What if America had beaten Japan to the legendary 2JZ engine by decades? What if we had built a lightweight Porsche killer before Porsche? Believe it or not, we did. In the 1960s, GM engineers were cooking up radical ideas—an overhead-cam inline-six in the Pontiac LeMans “Sprint” and a rear-engine sports sedan (Chevy Corvair). This tech should have dominated for decades. Instead, botch cars went out with a whimper.

1. The Chevrolet Corvair: America’s lost Porsche fighter

The Corvair was Detroit’s wildest mass-produced experiment: a rear-engine, air-cooled, flat-six car that came out before the Porsche 911. “The Chevrolet Corvair’s history is one of triumph and trials, but it is undeniably one of the most fascinating in American automobile production,” says the Western Reserve Historical Society. It was also packed with firsts: first mass-market American car with a rear-mounted engine, first with independent suspension on all four wheels, and the first to use turbocharging.

At launch, MotorTrend called it “the most significant car of 1960,” praising its “engineering advancement: its (aluminum) aircooled engine, transaxle and four-wheel-independent suspension.” Chicago Tribune pointed out that the Corvair had “GM’s first all-independent suspension”—a move meant to take on European sports cars head-on.

So what happened? Bad PR. The Corvair got a reputation for dangerous handling, fueled by Ralph Nader’s Unsafe at Any Speed book. In 1971, the National Highway Traffic Safety Administration cleared it, saying it was “no less safe than anything else on the road in the early 1960s.”

But the damage was done. GM cut its losses and moved on, leaving us wondering what if?

2. The Pontiac LeMans Sprint: The American 2JZ that could have been

Now, let’s talk about the engine America should have kept building. In 1966, Pontiac dropped an overhead-cam inline-six into the LeMans. It revved high, made great power, and sounded like no other American car. According to Regular Car Reviews, “America could have had our own 2JZ in 1966… a 56-year-old American car with an overhead camshaft inline six that revs like a vacuum cleaner.”

The man behind it? John DeLorean. Yeah, that DeLorean. He wanted an American engine with European engineering. According to Regular Car Reviews, “John DeLorean essentially made the first 2JZ… but he was too scared to keep doing it.” He brought back a high-revving inline-six with a belt-driven overhead cam—technology that wouldn’t take off in the U.S. for decades.

The LeMans Sprint’s OHC-6 had an aluminum head, a belt-driven cam, and a sporty Sprint trim that made 207 hp. But Americans wanted V8s. A few years later, the engine was dead. If GM had stuck with it, we might have had a factory turbo inline-six muscle car by 1970. Yeah, let that one settle in.

What could have been?

Now imagine a world where GM put these technologies together. A turbocharged, lightweight, rear-engine American sports car—one that crushed muscle cars in a straight line and embarrassed European exotics in the corners. In the 1960s, GM had the tech. They just didn’t have the buyers. Some of the best engineering of the decade faded into obscurity.

You can see Regular Car Reviews take the Pontiac LeMans Sprint on the track in the video below: