850cc Modified Hydro (850ccMH), Also known as Formula E, or FEH
Engines:
40 cubic inches up to 49 c.i. manufactured as a service engine and associated carburetors. Exceptions are the Mercury MK75 6 cylinder, Mercury 650 xs, and Mercury 4 cylinder 62 c.i.
60 and 62 cubic inch 4 cylinder 650s are allowed.
