Honda is interested in joining NASCAR if budgets make sense, but a switch to the championship would likely mean the end of its IndyCar and IMSA programmes.
In America, Honda currently supplies engines for IndyCar and runs a dual programme - via its luxury and performance brand Acura - in the IMSA SportsCar Series.
Toyota was the last new manufacturer to join the NASCAR Cup Series, in 2007, but Art St Cyr - the vice president and business head of auto operations for American Honda Motor Company - said the firm is watching with interest ahead of the introduction of the next generation of Cup car for 2021.
"We always keep an eye on it," said St Cyr, speaking after Acura's Petit Le Mans win. "We look at it peripherally, right now. But it is something that interests us.
"Given the opportunity, we'd jump at the chance to do that as soon as it makes sense for us." St Cyr added that the scale of NASCAR's challenge and reach is both an attraction and a deterrent in terms of the effort required.
That would mean Honda likely switching its attention solely to NASCAR at the expense of its other motorsport activities.
"From an engineering exercise, I'd love to do it," he said. "But it's a question of cost versus benefit, and honestly bandwidth.
"Because NASCAR is a huge undertaking, with 38 races and a lot of cars and engines to build each year, so it becomes a capacity issue.
"We can do IndyCar and IMSA and those types of things, or we can do NASCAR. And that's not just cost-wise, that's overall capability.
"We do all of our development, all of our engine builds, out of our HPD office at Santa Clarita.
"It has physical walls, and there's only so much throughput that can happen inside them.
"To do NASCAR, say you need four cars, I don't know but I'd imagine it's maybe 20 engines per car, so you're looking at minimum of 80 engines [per season].
"That's a lot of engines you gotta crank through."
New NASCAR chassis rules for 2021 will be followed by an updated powertrain in either '22 or '23, with both moves aimed at slashing costs and attracting new manufacturers to join Chevrolet, Ford and Toyota.
Some form of engine hybridisation is also expected to be a part of the new powertrains, to make them more road-relevant to manufacturers.
St Cyr said he was encouraged by NASCAR's Gen-7 new car plan to reduce costs, coupled with the leadership shown by its chairman and CEO Jim France that he's also experienced first hand in IMSA.