The top-level series currently has three manufacturers in Ford, Chevrolet and Toyota.
It last had four manufacturers in 2012, Dodge's final season before it pulled out of NASCAR.
Other manufacturers, including Nissan, which has a sizable presence in the American automobile market, have been linked to the series.
NASCAR president Steve Phelps said there is a "ton of interest" in the paddock in adding new manufacturers.
"The great news is that the three OEMs that we have - Ford, Chevrolet and Toyota - are all interested in having another one. Maybe even two," Phelps told NASCAR digital media.
"But the process is long. We won't see something obviously for 2019, we won't see something for '20.
"I'm confident that in the future we will have a fourth OEM and if we're lucky enough to have a fifth, that's great.
"I do think we'll have some success there, but it will be, I would say, years down the line."
Hybrid power in the future?
In NASCAR's yearly address to the media, Phelps also discussed the idea of alternative power in its championship.
Penske's Brad Keselowski has previously advocated hybrid power in the Cup series.
"Is electrification on the [agenda] in the future potentially? Yeah, it certainly is," said Phelps.
"Can I see a time in the future that we will have that? I definitely do.
"When we get there, how we get there, what it looks like, there's a lot of work to do between now and then.
"But I can assure you that we are looking at it right now."