Ford 272 C.I. runs low 11's. Why do Mopar guys need 408's?

Nines are fast, at least in my opinion, but I want to run 10.teens, or 6.40s, to avoid all the stuff that goes with nines (though my car has all the safety stuff necessary for nines, short of a chassis cert).
If any of my closest tracks ran index races, or something like SEGA, I'd start building something tomorrow.