Forza Motorsport 6: Apex

From the main menu:

Free Play
Select Track > Top Gear > East Circuit (Day)
Select Car > Ford Mustang Boss 302
Game Options > Max Drivatars - 15, Drivatar Difficulty - New Racer, Limit Drivatar Aggression - On, Laps - 2, Collision Mode - Always Off
Assists - Do whatever you're comfortable with, but change braking to at least 'ABS on' so it doesn't slow you down when coming to a corner

Start the race and go full throttle until you see the red braking line. You can go ham into the turns and break a bit past where it turns red but keep the wheel straight. Cut the corners tight and slam the throttle again. May take some trial and error but you will get the hang of it. Two laps because I was not able to catch up to the first car fast enough on the first lap.

Go onto free play, set the track as the third top gear track as it's the shortest. Then make sure max drivatars is on and select the car as 1969 Ford Mustang Boss 302.

Simply win the race and then the achievement will pop :)