[Unique427]

Sitting for +10 years suggest that all 4 tires are likely beyond a 10 year service life.
Check the production date code (month/year) on the sidewall.
As a tire ages, rubber compound hardens and alters grip characteristics.
Another consideration is after 10 years odds of a blowout increase substantially.
This is why tire shops don't repair flats on tires beyond 10 years.

I also sort of feel unless that SPF is well documented its overpriced for a 351.