[Jeff Lee]

Passenger compartment is from firewall to rear bulkhead, door to door and roof to floor. Even if it were legal in the passenger compartment, if I were a tech and saw that "hidden" behind anything I would be doing some investigating!
Personally I would want the lines as short as possible so on your AMC it would be passenger side inner front fender or firewall. If you can mount it vertical you might consider it on the passenger side radiator support.
It's about time NHRA allowed these in Stock!