Every few years, a car undergoes a major transformation. Buyers, realizing big changes are coming, wait to spend their money on the new machine.

It’s a dynamic as old as Detroit, but certainly not unique to it (see: iPhone, Apple).

At the moment, this pre-release slump has set in on the granddaddy of American sports cars: Chevrolet’s Corvette, the most collected car in America, is about to be reborn.

Until then, though, no one seems to want the angry thing.

Since its 1953 debut, the Corvette has been overhauled seven times. This time, however, the swoon in advance of the big unveiling is particularly pronounced, in part because General Motors is drastically changing the car.

Its engineers have moved the engine from the front – where it has always been bolted – to the middle, behind the driver’s head and in front of the rear wheels.

The swap moves the American sports car in line with competitors from Ferrari and McLaren who argue that the mid-engine layout makes for a more balanced car.

The Corvette clan is ready. “We’ve been taking deposits for a rumored mid-engine Corvette since 2014,” said Sean McCann, floor manager at Stingray Chevrolet near Tampa, Florida. “People are canceling their orders (on 2019s) and starting to hold back, because they want to wait and see what’s going to come out.”

Corvette sales in the U.S. have declined every quarter from the prior-year period since 2016. Dealers sold just 18,791 of the vehicles in 2018, 44 percent less than in 2015. Current models are idling on dealership lots, forcing dealers to offer large incentives. Stingray, for example, is dangling discounts and incentives up to US$15,000 on some of the high-performance models.

If you’ve always wanted a Corvette and don’t care where the engine goes, now’s the time to buy one.

General Motors declined to talk about the big Corvette upgrade or the sales slump, though the company did confirm a reveal date for the new car: July 18, in southern California.

The Corvette is a so-called “halo car.” Its primary job is to shine so brightly on glossy magazine covers that the luster carries over to the local dealership floor and illuminates the greater Chevrolet galaxy, from the thirsty Silverado to the circumspect Sonic. From that perspective, the new ‘Vette is already doing just fine.

The tricky thing, however, is that the Corvette is one of the rare speed machines that contributes significantly to the bottom line. General Motors makes a tidy profit on each one, and it typically sells a lot of them. At its peak in 2006, Corvette sales approached 37,000 in the U.S., roughly level with the Volkswagen Beetle and Lincoln Town Car.

Sports cars in general are having trouble keeping up with the rest of the auto industry. Annual sales in the U.S. slid 22 percent in the past three years, as buyers clamored for SUVs of all shapes and sizes. Carbon-laced speed machines are expensive, and those who can afford them, mostly older buyers, are fast losing the physical capability to drive them—or at least get in and out of them.

Jonathan Klinger, a spokesman at Hagerty Insurance, said the coming Corvette is a bid to attract younger buyers to the brand. McCann, at the dealership in Florida, is expecting a tide of customers who otherwise would be kicking tires at more exotic dealerships. Barring an economic meltdown, the depth of the swoon should reflect the scale of the coming Corvette boom.

Tony Fiorello, president of a dental implant company in Florida, will be one of many padding the sales stats for Chevrolet. He wanted the first mid-engine Corvette so badly he hedged his bets. In 2017, he put down two deposits, one for the 2019 version and one for the 2020. “It’s a paradigm shift,” he explained. “And I just knew that I wanted to be No. 1 on the list.”

The 2019 model is now in his garage. He drives it regularly, and has no plans to sell. Eventually, he figures it will be a collectible: the last of the front-engine Corvettes.