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Grand National

The Grand National (GN) endurance race was once 100 miles or more. (The boats must carry 50 gallons of fuel.) Today a GN race may be 5 miles, one hour, two 10-lap heats, or a combination of the above. Grand Nationals draw crowds to the riverbanks to hear the roar of engines and feel the suspense: Who can hold out to the finish line? The class uses any V-bottom or monohull up to 25 feet long. No tunnel over 1 inch deep, hydroplane or step-type hulls are allowed. The GN race boat is propeller-driven, powered by a U.S.-made automotive or light truck Chevrolet or Chrysler engine mounted rear of amidships.

Big block boat engines
Minimum Age: 
18 years old
Chevrolet Big Block, Chrysler B/RB or Chrysler Hemi-based engines. Supercharged = 475 c.i max, Naturally Aspirated = 525 c.i max.
100+ MPH
Minimum Weight: 
No minimum; average is 2500 lbs.
Gasoline only with no additives
Monohull - V-Flatbottom; No tunnel over 1 inch deep, hydroplane or step-type hulls allowed.
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.
Engine Block: 
Cast iron engine blocks only
Cylinder Heads: 
OEM or aftermarket. Iron or aluminum with common wall intake ports
In block, any style. Overhead cams are not allowed in this class.
Must be Roots type blower
Max Overdrive: 
8-71: 1.03:1, 10-71:0.95:1, 14-71:0.83:1
Any except for turbochargers
Est. Horsepower: 
875HP - 925HP
Straightaway Record: 
116.263 MPH
Current National Champion: 
Body Snatcher GN-24 Ted Kolby