Conversation so far:
What was his first race on the Indy Circuit?
In 1962 Thompson entered three John Crosthwaite designed cars in the Indianapolis 500.
How did he do?
Unusually, they used a stock V8 Buick engine and it was in the rear unlike the front engined, race tuned, Offenhauser powered cars used by most competitors.
It.

Question: How did  the change in design affect the performance?
Self-contained rewrite: How did the engine change affect Mickey Thompson's performance in his first Indy Circuit race??