Whoa, you're all over the place! Good thing you "only" want
-30 years of competition records
-30 years of financial records
-30 years of legal records
>Is it possible
Short answer: no. Long answer: yes, if you had a couple
hundred grand to spend on the project.
Try something simpler. Pick an event from 1972. Oh wait,
start even more basic: what events were there in 1972?
Ok, say you pick one. Now try to figure out with certainty
what years it ran. There's a project right there. That
will take you three weeks and a couple airplane trips.
Now try to find results from those rallies, or entry
lists. Yikes!
I think there are some people (like, maybe a dozen) people
in the US who have some (perhaps 20% collectively) of this information
in their head.
However, I'm not sure it's necessary: I don't know (but I'm
not in the dozen!

) any situations where roads were
refused because there wasn't a 30 year safety record presented.
It seems it's mostly "You've got insurance? OK!" and after that
the only concern is 'fugative dust' or something ridiculous.
Cheers,
Anders