Rain worked against NASCAR again, postponing Wednesday's Sprint Cup Series test of a new rules package for Kentucky Speedway to Thursday.

Teams will practice from 11 a.m. to 1 p.m. on the bumpy 1.5-mile track in preparation for Saturday night's 400-mile Sprint Cup headliner. Drivers will be trying out new specifications designed to reduce downforce and produce more passing. Rear spoiler heights were reduced from 6 to 3.5 inches, the front splitter was expanded by 25 inches and an overhang reduced by 1.75 inches.

Though intermittent showers let up enough to provide hope of an evening practice, NASCAR spokesman Kerry Tharp said lingering wet spots forced the postponement.

"There were weepers in multiple areas," Tharp said. "We kept at it and kept at it, and it just wasn't conducive for us to put on practice."

Wednesday's weather issues follow Sunday night's race at Daytona that was delayed by rain until just before midnight.

The delay provided drivers and teams some extra down time following Monday's scary finish at Daytona that ended just before 3 a.m. Dale Earnhardt Jr. took the checkered flag ahead of a multi-car wreck that sent Austin Dillon's No. 3 Chevy airborne into a catchfence before the remains of his destroyed car came to rest upside-down on the track apron.

Dillon emerged from the crash unscathed, but the spectacular wreck drew more scrutiny to restrictor-plate racing many believe has bunched cars together like sardines. That certainly isn't the issue at Kentucky as much as single-file racing, which has also been criticized.

Brad Keselowski's dominant victory last June offered evidence that change was needed after he led seven times for 199 of 267 laps. Keselowski, teammate Joey Logano and Kyle Busch combined for just 12 lead changes.

NASCAR announced new rules for Kentucky last month in a quest to improve competition. Cars are expected to cut about 1,000 pounds of downforce with the package.

Another set of changes were announced Tuesday for Indianapolis, Michigan and Darlington.

While Kentucky weather forced drivers to wait another day to see what effect the new rules will have, Carl Edwards seemed excited about them for himself and spectators.

"I really believe in this sport there are two types of fans," Edwards said during the delay. "There are fans that really like the race and like to see the guys get the cars balanced and manhandle the race cars and do all that, and they understand it. And I think there are the fans that believe that just because cars are closer than that means it's a better race.

"I don't know about the way this will look, but it puts it more in the driver's hands and to me that's a neat style of racing."