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: Any
Cubic Inches Limits: Supercharged = 475C.I. max.
Naturally Aspirated = 525 C.I. max.
Blower: Must be Roots type Blower
Max. Overdrive:
8-71: 1.03:1
10-71: 0.95:1
14-71: 0.83:1
Fuel: Gasoline only, no additives(nitro)
Induction: Any (except Turbochargers). Intake manifold must be cast (no sheet metal)
Ignition: Any
Estimated Horsepower: 875-925
Estimated Top Speed: 100+