Michael Andretti likes the new IndyCar universal body kit. He likes the look. He expects it will eventually save Andretti Autosport money, although the start-up costs have been “so expensive,” he said, for his four-car team.

But how the first-year application will impact the most important race of the season concerns him, and he won’t be able to alleviate his concerns until cars begin practicing for 102nd Indianapolis 500 in May. Andretti hopes the switch from Chevrolet- and Honda-produced bodywork to a uniformity won’t sour the very special recipe his team struck upon in winning three of the last four 500s with Ryan Hunter-Reay (2014), then-rookie Alexander Rossi (2016) and Takuma Sato (2017).

“I’m very worried,” Andretti said during a break in testing on Wednesday at Sebring International Raceway. “Whenever you change anything and you don’t know what you have, until you’re out there, yeah, I’m worried. We’ve had such a good package since 2012 at least, so… I don’t see how it can be any better than that, so that’s what worries me.”

Rossi, perhaps buoyed by having won half of his Indianapolis 500 starts, seemed confident his manufacturer and team would adjust.

“Honda had an advantage, but we were beating other Honda teams, so you’d like to think the package that we have is good there,” Rossi said. “They’ve proven that over the past five years. You obviously have to work very hard to make sure you stay in that window and are still executing at the level you need to win, but I don’t see any reason why we couldn’t go back to Indy and have the same kind of opportunities we had there in the past.”

Andretti won’t be placated until he sees his Hondas maneuvering to expectation in traffic around the 2.5-mile speedway.

“There’s nothing we can do. We don’t know if we’ll be able to draft off the car in front or we’re going to be able to pass them, are they going to take all the air off the car,” he pondered. “We don’t know. Until we get there, we’re not going to know. You can’t simulate another car front of you. By yourself, it’s fine. It’s when you have other cars.”

Andretti’s Hondas were particularly foreboding in 2016, when Rossi won on a fuel gambit, with teammate Carlos Munoz second and the cars of Ryan Hunter-Reay and one-off teammate Townsend Bell dominant early before they collided on pit road on Lap 117. Sato passed Helio Castroneves with five laps left to win the race for the first time last May.