Fontana race gets shorter and wider

Choosing favorites to win the NASCAR Sprint Cup Series race in Fontana once was fairly straightforward.

It’s now a bit complicated.

Jimmie Johnson and drivers for the Roush Fenway Racing team, led by Matt Kenseth, remain among the odds-on choices to finish well as stock-car racing returns to Auto Club Speedway on Sunday.

Johnson not only has won the last five Cup championships, the Hendrick Motorsports driver also holds the record for Fontana wins with five. Kenseth and Johnson teammate Jeff Gordon are next with three wins apiece.

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But those all came in 500-mile races on the sweeping two-mile oval track, where the 43-car field often was strung out and where Johnson and a few others excelled with cars that found the optimum mixture of horsepower and handling as they hit 200 mph on the front straightaway.

Then in the track’s race last October, the distance was cut to 400 miles and — whether by coincidence or not — the dynamics of Fontana’s racing changed and sparked an unusual and rousing outcome.

Tony Stewart held off Clint Bowyer and Johnson to win that race, Stewart’s first victory at Auto Club Speedway in 19 attempts over 12 years. It was Bowyer’s best finish there as well.

A spree of caution periods also produced some wild restarts that day, with the field often spreading four and five cars wide after the drivers took the green flag.

So NASCAR and Auto Club Speedway are sticking with 400 miles for Sunday’s Auto Club 400. It’s now the only Cup race of the year at Fontana, which formerly hosted two annually but lost one this season after it struggled to fill all of its 92,000 grandstand seats.

“A 400-mile race is going to be every bit as exciting, if not more, than a 500-mile race,” said Stewart, a two-time Cup champion.

“I thought the racing last year was really good,” he said. “The restarts early in the race were out of control. We were five-wide sometimes, and I know because I was one of them that put a bunch of guys five wide.”

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Kurt Busch of Penske Racing hasn’t won yet this year, but, through four races, he leads the Cup standings by a single point over Carl Edwards, the Roush Fenway driver who won at Las Vegas this month.

Stewart and his teammate Ryan Newman are tied for third, 12 points back. Busch and Edwards also are former Fontana winners.

Kyle Busch, Kurt’s younger brother, won last Sunday at Bristol, Tenn., and won his first Cup race at Fontana in 2005.

Even so, Kyle Busch said he typically has his hands full driving his Joe Gibbs Racing Toyota at Auto Club Speedway. “We’re always like a fifth- to ninth-place car,” he said. “Hopefully, we can get a little bit better than that.”

Fan favorite Dale Earnhardt Jr., with two top-10 finishes so far this year, is ninth in the standings but continues looking for his first win in more than two years. His last came at Michigan International Speedway, a track similar to Auto Club Speedway.

“California is a track I need to run better at,” said Earnhardt, who has never won at Fontana and has only three top-five finishes in 18 races there.

Trevor Bayne, the 20-year-old who shocked the motor racing world with his Daytona 500 win last month, also is entered at Fontana as part of his limited Cup schedule this year.

Qualifying is Friday, starting at 4 p.m. The Royal Purple 300 race in NASCAR’s second-level Nationwide Series is Saturday at 2:30 p.m., and the Auto Club 400 starts Sunday at noon.

james.peltz@latimes.com