the main problem is the aero-model in lfs
1: in nascar usually the cars are much closer together (compare it with nascar 2003) so you always drive in a pack of people. in lfs the aero-model is not like it should be in real live, so people get away from the pack which is impossible in real live unless you have some other cars going with you. the aero in nascar is quite the oposite, if there are more people together they go faster then a single car. in lfs you normaly slow down if you drive in the pack. and that is the main fascination in nascar. those close fights with lot of cars in the reach of the win. (compared to a circuit track, you have 3 maximum 5 people who can win, and you can tell who those 5 are right at the start or in lfs, right after turn 1)
2: in lfs we have maximum of 20 cars on track, nascar has much more, which brings out more action. i*ve seen a nascar race from 2005 where 15 cars were in the last lap in the lead lap and had the possibility in the end to wind the race. which kind of racing can offer that kind of finish? in lfs you always have a critical amount of people on the the track. if there are less then that amount of people with the same driving skill on the track it is just like hotlapping. on the oval you need at least 16 people to have it interesting to watch. (for driving it is even fun if you have 1 other guy that is at the same speed with you)
3: lack of strategy possibilities in lfs (taped grill, resistor plates, asymmetrical tires and stuff) we only have tire wear/heat and fuel, so if the race length is not set properly all cars have to pit at the same time. if you set the race-length to something like: if someone drives slow and does not need that much fuel, he can go with a stop less. or if someone goes for one more stop but times them with possible pacecar phases so he does not loose laps he can win
4: the tracks: nascar has more then 20 tracks and therefore variety. we have two ovals (normal and reverse). which we have to customize with layouts to get variety. and the autoX which is completely flat.
5: the closest nascar like car we have is the xrr, but it isn't really like a stock car in nascar. even not when you compare it to the COT but at least it is close...
6: pacecar: there is no possibility to have that kind of stuff automated, so we are depending on a human doing that. and of course the rules in pacecar phases with single/double-file is not clear to everyone so you can't do that on a public server.
so with the lack of the proper tracks, car, aero-model and strategy possibilities it is no wonder why watching oval races in lfs is not that catchy at all.
so in conclusion to that we can't have nascar at the moment in lfs, but we can have a league which trys to get as close as possible to it. which i am trying to get running. with compromise you get a proper car, strategy and tight racing but not the same like with nascar where 30 cars driving in a huddle.
not now but maybe in the future
btw. Nascar runs circuit races as well on wattkins glen but there you have the same problem again, the top 5 of the starting grid are mostly those guys for the win. allthough the cars are almost unified. i like tight circuit racing as well. i am nowhere near the fastest one, but hey in the middle is the most action, right