Conversation so far:
When did Alan Kulwicki start racing?
Kulwicki began his racing career as a 13-year-old kart racer.
Was Alan Kulwicki able to race cars at the young age of 13?
Kulwicki began his racing career as a 13-year-old kart racer.
What type of racing did Alan Kulwicki do at 13?
Kart racing or karting is a variant of motorsport road racing.

Question: Was he a successful race car driver?
Self-contained rewrite: Was Alan Kulwicki a successful race car driver?