Inboard Endurance
(Grand National) Racing

Today's Grand National boat owes its heritage to the marathon races of the 1960s and ’70s. These grueling races tested man and machine over distances of 100 to 500 miles over two days. Endurance was key. The fabled Parker and Miami 9-Hour Enduros challenged hull and engine builders to craft the strongest, fastest boats possible.
Many great drivers and celebrities have tried Grand National racing. Red Adair (famous for fighting oil well fires); race car drivers Parnelli Jones, A.J. Foyt and "T.V." Tommy Ivo; astronauts Virgil “Gus” Grissom and Gordon Cooper all competed in Inboard Endurance races. Even Elvis took a GN for a lap or two; remember “Clambake”? Many performance boating legends drove, built or designed marathon hulls and hardware. They include Powerboat Magazine founder Bob Nordskog, motorsports legend Mickey Thompson, stunt pilot Skip Volk and Vic Edelbrock. Some of the original performance boat manufacturers also contributed to GN racing: Rudy Ramos (Rayson Craft); Len Schiada (Schiada Boats); Nick Barron (Hallett Boats); Howard Brown (Howard Boats); Bob Patterson (Patterson boats); Grier Rush (Rush Performance Boats) and Lou Brummet (Mandella Boats).

Today’s races generally run about 15 minutes each, with an occasional 30-minute or 1-hour event. The all-out “push it as hard as you can, hope it holds together” attitude has always been the trademark of a great GN race. From the drop of the green flag launching the crowd-pleasing Le Mans start, through the checkered flag signaling victory, you are guaranteed to enjoy the show. Grand National Specifications

Length: 25 feet maximum

Weight: No Minimum (average approx. 2500 lbs.)

Hull: Mono Hull - vee / flatbottom

Propulsion: American-made automotive engine mounted to rear of amidships and driving forward through a v-drive to a stationary strut mounted propeller.   
Gearboxes are permitted.

The GN Engine:   
Block: Chevrolet Big Block, Chrysler B/ RB or Chrysler Hemi-based engines. Cast iron engine blocks only. Cylinder Heads: OEM or aftermarket. Iron or aluminum with common wall intake ports.Cam/lifters: In-block, any style. No overhead cams.Oiling System: AnyCubic Inches Limits:     Supercharged = 475C.I. max.
Naturally Aspirated = 525 C.I. max.Blower: Must be Roots type BlowerMax. Overdrive:8-71: 1.03:110-71: 0.95:114-71: 0.83:1Fuel: Gasoline only, no additives(nitro)Induction: Any (except Turbochargers). Intake manifold must be cast (no sheet metal)Ignition: AnyEstimated Horsepower: 875-925Estimated Top Speed: 100+