Beginner Road Track Racing: Feedback on Engine Options Wanted

Competitive? What if the guy just wants to have fun and loves these cars?
That is how I am. I want to do some stuff like this eventually. I would use an A body though just because while I'd prefer a B body, the replacement cost of a 68-70 B body car is outrageous. A 73-76 A body roller can be found for well under $1000.
Fair point, although I will counter with, rarely in any kind of racing does it start with “let’s go have fun” and not end with “how can we be more competitive” or “how can we go faster?”