Here is the full list of all 33 Tony Stewart's Sprint Car Racing achievements worth 1,000 gamerscore.
Won 100 races
Won 10 races in Online Multiplayer
Won a season in a 410 Sprint Car
Completed a season in a 410 Sprint Car
Won a season in a 305 Sprint Car
Won 75 races
Raced at every track
Won 50 races
Started a team racing 410 Sprint Cars
Won a season in a TQ Midget Car
Completed a season in a 305 Sprint Car
Won 25 races
Started a team racing 305 Sprint Cars
Completed one season in Career
Completed a season in a TQ Midget Car
Won 10 races
Won a 100% length race
Completed a 100% length race
Bought a part in Career
Started a team racing TQ Midget Cars
Won a race in Career mode
Completed 10 races in Online Multiplayer
Won a race in Online Multiplayer
Created a character
Created a custom car
Completed a race in Online Multiplayer
Won a race
Win 200 races
Win a race in split-screen
Win 4 split-screen races in one session
Complete 5 seasons in Career
Complete 10 seasons in Career
Earn $5,000,000 in Career