Horsepower packages are similar to 2020, but NASCAR made a change at DarlingtonOne of the first things a casual or new NASCAR fan asks is what makes the Cup Series cars go and what kind of horsepower is under the hood. Some race enthusiasts might think it’s a stupid question as if, “see car, put gas in car, start your car and drive your car.” There is a simple logic to that, except when it comes to racing, there are some significant differences.The first part is the fuel that goes into stock cars. It’s the same 98-octane you might see when you pull in for a fill-up, but the Sunoco Green E15 that fills NASCAR tanks is a unique blend just for high-performance engines. The gas is actually green in color and used across all three national series.We want to get 2021 started off on a positive note! 😃Reply and tell us something good that has happened to you or that you are looking forward to this year so everyone can have some good news as the new year starts! pic.twitter.com/13ymmuVjPm— Sunoco Racing (@SunocoRacing) January 13, 2021NASCAR isn't just about horsepowerThat was the easy part. Now comes the part that will have some shaking their head and saying, "What?"The NASCAR Cup Series runs two separate horsepower packages, 550hp and 750hp, depending on the track. But regardless of how many horses are galloping under the hood, several other factors determine how fast they go.The cars licensed for consumer use can run anywhere from 70-200hp or more, depending on the vehicle's brand, model, or size. Some of the golf carts at tracks can probably go as fast as a 78hp Mitsubishi Mirage. And they’re battery operated.Bill Elliott has the fastest qualifying speed record of 212.809mph before NASCAR used restrictor plates.A 550hp engine used for the Daytona 500 is not the same as Atlanta Motor Speedway. A restrictor plate is put on top of the carburetor at Daytona International Speedway (as well as Talladega Superspeedway), limiting the motor's power, slowing acceleration, and lowering overall top speeds. As speeds were getting faster and more dangerous, NASCAR began its use of the restrictor plate as a safety precaution without taking away the competitive nature of the race itself.You might also like: What does NASCAR stand for?For the most part, 750hp engines are used on tracks not noted for speed, but for acceleration. They are:Bristol Motor Speedway (both oval and dirt)Charlotte Motor Speedway RovalCircuit of The AmericasDarlington RacewayDaytona Road CourseDover International SpeedwayIndianapolis Road CourseMartinsville SpeedwayNashville SuperspeedwayNew Hampshire Motor SpeedwayPhoenix RacewayRichmond RacewayRoad AmericaSonoma RacewayWatkins Glen InternationalYou can add Darlington Raceway to that list for 2021. The South Carolina venue used 550hp previously, but NASCAR is going with a 750hp, low downforce package for both races (May 9 and Sept. 5).A lil throwback for your Thursday feat. a 🐐#NASCARThrowback x #TBT pic.twitter.com/StiO0S7U8b— Darlington Raceway (@TooToughToTame) February 11, 2021NASCAR will mandate the 550hp package at the following tracks:Atlanta Motor SpeedwayCharlotte Motor SpeedwayAuto Club SpeedwayHomestead-Miami SpeedwayKansas SpeedwayLas Vegas Motor SpeedwayMichigan International SpeedwayPocono RacewayTexas Motor SpeedwayYou might also like: Road courses bring new excitement to the NASCAR 2021 schedule