Conversation so far:
when did Alan start racing?
Kulwicki began his racing career as a 13-year-old kart racer.
who made the karts for him?
Kulwicki asked his father for advice, he typically ended up doing most of the work himself.
"I showed him how", Gerry Kulwicki said.

Question: when did Alan start racing cars?
Self-contained rewrite: When did Alan Kulwicki start racing cars?