205.157-3—Configuration identification.
(a)
A separate vehicle configuration shall be determined by each combination of the following parameters:
(1)
Exhaust system (engine): (i) Mufflers; (ii) expansion chambers; (iii) spark arrestors; and (iv) other exhaust system components.
(2)
Air induction system (engine): (i) Intake muffler; (ii) intake ducting; and (iii) air cleaner element.
(5)
Cooling system configuration: (i) Natural air cooled; (ii) liquid cooled; and (iii) forced air cooled.