NASCAR engine AFR
 

I was watching some of the nascar race yesterday, BTW, no wonder NASCAR is dying. nobody can pass, they don't lift and they mostly ran in a single line.
on the in car camera, you could see the dash. on the left it "looked" like it was displaying AFR. it was showing around 14.5 at 3k under caution and 14.1 at 8300.
14.1 seems lean though.
I thought it would be richer.

lean is mean

14.1 is lean for full throttle and full power, but in the long run is probably the most efficient.

Max power would be reached at closer to 12.5 to 1 but if running that rich that required more pit stops, probably wouldn't be worth it.

Restricter plate plus gas mileage wins.

Yup. That's what makes it so exciting.

Fixed it for you.

This. 14.7 being stoich, 14.1 is not terribly lean. Sooo many things effect power output.

also depends on what they are running for fuel.

^^ Bingo! NASCAR runs Green E15 with a stoich AFR of 14.

https://www.sunocoracefuels.com/fuel/green-e15

And it is all just spec car racing. The same chassis, the only difference is the "body shape" and the engine brand that the sponsor wants to pay the bill.

When you are part of "the pack" it takes less than full power to maintain that speed, so the lean condition is most likely set that way to optimize the pack racing mentality, and not full bore passing/racing of a short track.

Restrictor plate racing is a waiting game, with the goal being to still be running, and moving on the final lap (hopefully in the lead pack). Only this will give you a chance of winning the race.

Better fuel mileage will directly impact the length of each pit stop, which will gain you track position over someone who isn't dialed in efficiently. (each 1 second in the pits, is 100 yards on the track.)

Which makes 14.1 VERY lean.

Conserving fuel as a strategy is no different than F-1 cars slowing down to save their tires.

Both are a result of rule-makers manipulating the rules in an attempt to make the racing more interesting.
But that usually results in exactly the opposite.

Real men don't want to waste time watching a parade.