ORANGE, Calif. - In 1968, college teachers Charles Betz and Fred Peters went to look at a busted-up Ferrari that a fellow car collector was selling for $1,100.

A wreck had destroyed the body of the 1954 375MM Spider convertible. The engine was missing. The chassis had been chopped and shortened.

The price was too high. But the Spider came with an extra set of wheels, and Betz had seen driver Dan Gurney race the car - capable of speeds over 170 m.p.h. - at the 1958 Times Mirror Grand Prix in Riverside, Calif. He knew what the car had been, and could be again.

The collectors resolved to find the missing parts, restore the car to its original glory, and sell it for a profit. They didn't know then that the task would take decades, outlast their marriages, compromise their bank accounts, test their patience, and ultimately earn them millions.

Betz was a college economics professor who bought and restored English and Italian sports cars. Peters taught psychology at a different college and specialized in German cars.

In 1966 they attended a dinner party thrown by a friend, who thought the two professors who loved old cars would like each other.

They did. Each admired the other's tactics with classic cars.

"He was smart," Betz said. "Rather than buying impractical cars, like me, he was buying Volkswagens."

"Charles was more sophisticated than I was," Peters said. "He was working on MGs and Austin-Healeys."

They bought and sold Porsches, Jaguars and Maseratis, generally breaking even. They acquired and restored Alfa Romeos, always seeing gold but never turning a profit.

Often, they had to sell a car to buy a car, or borrow money from Peters' mother or from finance companies, to close a deal. On several occasions, Betz and Peters put up their furniture as collateral.

"It was a little distressing on my marriage," Betz said.

Trying to be more professional, they opened a used Ferrari dealership in late 1968. That lasted two years.

Ferrari parts also got expensive. A pair of original headlights for the 375MM cost $5,000. An exact replica of the grill cost $10,000.

But profits were going up, too. The two men began making money from selling parts they'd collected, but didn't need, for their own cars. They also sold cars for what seemed astronomical sums.

In 2002, the pair sold a rare 1957 Ferrari Testa Rossa they'd spent years restoring. Though the men are reluctant to identify the buyer, or disclose the sale price, it was their first really big score.

"My half of the profit on that car was more than I made in 38 years as a college professor - in my entire career as a college professor," Betz said. "So, we did all right on that one."

But they held on to the 375MM.

Betz's son Brooke, who now does much of the work on the partners' cars, estimated that the men put $400,000 into the engine alone, and at least $1 million in other parts.

After more than four decades, the car was showroom ready - Ferrari-red paint gleaming, 12-cylinder motor firing, chrome wire wheels shining. The wood of the steering wheel, the leather of the seats, and even the leather straps of the hood latches were restored to factory perfection.

In early 2014, the two men decided it was time to sell. They were ready to liquidate the collection they'd spent almost five decades assembling.

"When you're 75, and your partner is 83, you can't have a 30-year plan," Betz said.

In August, the two men put the 375MM on a flatbed truck and shipped it to Monterey, Calif., where during the annual Car Week it would go up for sale at an event conducted by the Mecum auction house.

Peters and Betz had reason to be optimistic. The week had already seen some record-breaking sales. A 1962 Ferrari 250 GTO had sold for $38.115 million - the highest price ever paid for a car at auction.

That hot, dry afternoon, the partners, along with Brooke, watched as collectors feverishly bid for their car - and then stopped before reaching the sellers' stated minimum. The top offer came in at just under $5.8 million.

It was tempting, but not enough.

A tired-looking Peters, wearing jeans, suspenders and sandals, stroked his wispy white goatee. Betz, in baggy shorts, sneakers and trifocals, sighed and shrugged his shoulders.

"In terms of what we've spent, we would have been way ahead," he said. "But we've owned it for 46 years, and $5.8 million just won't do it."

Back in Orange, where the partners store the 375MM and six other classic cars left in their collection, Peters and Betz continued to get inquiries. An unidentified collector had made an offer for the 375MM, but was unable to find buyers for the cars he needed to sell to raise the money. Another offered the same price, but couldn't finish the financing.

The men seemed almost relieved.

"The good news is that we like the car well enough to keep it," Betz said.

The car did look pretty good, all fixed up, sitting in the garage, Peters said, and selling their restored cars always came with "a little twinge."

"You put your heart into these cars," he said. "You remember what they were."