I'll toss in an easy one as well.
It's not going to be short but you can easily get a 105 speed rating with 500 laps so you'd get 52500 speed points.
Do Martinsville with the MENCS series, easy race mode, Normal tire/fuel, three stages, relaxed yellow, and no damage. Race so dirty it will feel like Eldora. https://1drv.ms/v/s!AsUOa7YS1T9PsLEtf_cCfUpyGpSCDA
That's how I raced a typical lap. Accelerate into Turns 1 and 3, riding the wall, letting off the gas. Once you drop down to third get back on the gas and cut the driving line hard. Accell back into the next turn and let off around the time that your engine tops out. Around lap 490 I ended up beating my previous best than what is shown there. Pit strategy is that you should only need to go in during the cautions. I kinda spun out racers at 380 so I could get gas and not lose too many positions. Or any at all. the easy AI is about a second slower so at the end 3rd place was 6 laps down and Johnson in 9th was 10 laps down.