NORTH WILKESBORO, N.C. — The last time NASCAR Cup Series cars turned laps at North Wilkesboro Speedway, the setting was an organizational test in the short, frigid days of mid-January. Weather for the return trip this weekend has been quite the opposite.

Searing mid-July heat toasted the speedway grounds Friday and Saturday as anticipation built for Sunday’s Window World 450 (7 p.m. ET, TNT Sports, truTV, HBO Max, PRN Radio, SiriusXM NASCAR Radio), the historic short track’s first Cup Series points race in nearly 30 years. Though Sunday’s main event will be held in the relative cooling of nightfall, temperatures cresting the 90-degree mark during the height of the day have created far different conditions for Sunday’s summertime showdown.

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“We did learn some things, but to say we learned what the balance needs to be to come back here in July is is pretty far-fetched,” said Spire Motorsports crew chief Ryan Sparks, who estimated it to be “about 30 degrees” when his driver, Daniel Suárez, tested the team’s No. 7 Chevrolet here last winter. “So with extreme temperatures this weekend, you know grip is going to be at a premium. So, but it’s good, old-fashioned short-track racing, just looking for mechanical grip. I’ve got a good group of guys that know what they’re doing here and looking forward to just getting on track. But yeah, the times that we’ve been here, I don’t think are going to relate at all. So you’re just going to have to go with your gut instinct on a lot of these calls.”

Sunday’s event will also be vastly different from a procedural standpoint. North Wilkesboro has been a part of the NASCAR calendar since its revival from the ruins for the 2023 schedule, but the last three seasons, the track has hosted the non-points NASCAR All-Star Race for a shorter field running a shorter distance. The return of a points-paying event will mean a full 37-car grid set for a record 450 laps, later in the year than the mid-May All-Star exhibition and with a full field filling the allotment of pit stalls.

Another new wrinkle — a potentially literal wrinkle — is a new front-bumper configuration for Cup Series cars on short tracks. The rules update makes its debut this weekend, and the removal of some energy-absorbing foam and other bumper bracing is expected to discourage drivers from initiating harsh contact by increasing the potential for cars to sustain damage more easily.

The concern that introduces for teams is the likewise potential for terminal damage to the front-mounted radiator, something crew chiefs will coach their drivers to manage — especially on a tight 0.625-mile layout where close-knit contact and restart jam-ups come with frequency.

“I mean, obviously it’s still a bit of an unknown,” said Paul Wolfe, crew chief for Joey Logano’s Team Penske No. 22 Ford. “We looked it over this week together and just kind of talked through it. I don’t think anybody really knows exactly how it’s going to react, but it’s definitely not going to be robust like what we’ve gotten accustomed to, right? So just being mindful. The radiator and all, that’s the biggest concern, like it used to be. That’s what used to happen. We’d have those big stack-ups and knock radiators out of them. So yeah, I think until we just get on track and really see what they are, I don’t think we’re really going to know what we have. So we’re mindful of it, and you try not to be the ones that have the first issue.”

MORE: Weekend schedule | Goodyear notes for North Wilkesboro

One factor that could provide a constant is the Goodyear tire configuration for the weekend, a familiar setup that’s been used in other short-track settings — most recently at Martinsville Speedway in late March. Cup Series teams put the package to the test Saturday evening in a 50-minute practice, topped by 2025 North Wilkesboro All-Star winner Christopher Bell.

The session was held later in the day Saturday after pole qualifying was washed out by afternoon storms, potentially giving teams a more apt comparison point that aligns with a 7 p.m. ET start time. While those rains provided a brief respite from the punishing heat, another scorcher is expected for Sunday, when teams are expected to fight anew for grip.

“I mean, obviously, we kind of know what our limits are with load, cambers, toes, things like that, so it puts us in a good spot coming here,” Sparks says. “But like I said, this is going to be such a different animal we’re having to attack, with just the style of this race track and the way it loads up itself, and then with the extreme temperatures. So you can’t do exactly what your historical notes show, but you at least have some good data points on knowing what has been a good direction previously.”