But as years have passed NASCAR's iciest sibling rivalry has thawed a little bit, at least to the point where they can joke around a little bit.
Kurt Busch did just that Friday after Kyle Busch edged him out by 0.002 seconds to take the pole for the Cup Series race Sunday at Bristol Motor Speedway.
"I can walk up to him and say, 'Yeah, I let you have it' and he will giggle. He will actually laugh," Kurt Busch said.
It marks the third time the Busch brothers have started on the front row together, and the first since 2013. In all three cases, Kyle started first and Kurt second.
"He always told everybody if you think I'm good, just wait for my younger brother," joked Kyle Busch.
Kurt Busch said he messed up in turn one, which cost him a shot at a second straight Cup Series pole.
"If I am going to get beat by somebody if I don't hit a perfect lap I would rather it be my little brother," Kurt Busch said.
There was a time when the Busch brothers rarely spoke at all.
But Kurt Busch said they do communicate now.
"It's better now with age," he said of their relationship. "Like wine, it gets better with time. You let it settle."
Last year the Busch brothers finished 1-2 at Sonoma with Kyle Busch holding off his older brother. There is a chance that could happen again Sunday as they were clearly the two fastest cars in all three rounds of qualifying at the half-mile track.
"It was tough years ago for a few times, but lately I guess we have been racing each other a little better," Kyle Busch said. "Overall we just need to keep trying to make sure they are good battles and clean battles and not ugly ones."
Things to watch at the Cup Series race on Sunday:
FORDS DOMINATE: Kyle Busch had the only Toyota in the top 10.
HARVICK'S TOUGH BREAK: Kevin Harvick will have to start Sunday's race at Bristol Motor Speedway at the back of the field after crashing in practice. Harvick's suspension broke on a practice lap in the morning and his car took a right turn into the outside wall.
Under new rules installed this year Harvick will have to start at the back of the field because he went to a backup car.
"It definitely wasn't a tire failure or anything like that, but just going in the corner as soon as I let off the gas it just hung a right, so it's unfortunate but we'll get another one out and do it again," said Harvick, who is fourth in the NASCAR standings and has six top-10 finishes in seven starts.
WHAT HAPPENED THERE: Harvick has company with some other top drivers starting at the back of the field. Denny Hamlin will start 25th and Martin Truex Jr. 26th after failing to get out of the first round of qualifying.
TURN FOUR SLICK: The track was a little slick with several drivers having some trouble coming out of Turn 4.