Some subtle differences are required to build an engine for drag boats, but here’s one not often thought about.

“We have to run the Big and Ugly air scoop rather than the carbon-fiber hat we run on our dragsters,” says Brandon Graham at KPE Racing. “We don’t have to worry about any of our dragsters ‘submarining.’ These hydro boats can literally dive into the water, and you do not want to destroy several thousand dollars worth of carbon fiber, so we stick to the Enderle hat.”

This 582ci big-block is set up for the Lucas Oil Pro Mod class. Rules are wide open enough that the boats run in the sevens, but reliability is highly desired, as well.

“As in many classes, consistency is the key,” adds Graham. “Using methanol and a Roots blower, we keep a nice tuning window open but it also allows us to lean on it, if we have to.”

The engine is built with a Lunati crank, GRP rods, JE pistons and Brodix BB@ cylinder heads fitted with T&D rockers. Induction is handled with an Indy blower manifold, Littlefield 14-71 high-helix supercharger and Enderle fuel system.

“One thing we’ve added is an injector spacer between the hat and blower,” says Graham. “This helps straighten out the air charge as we have the hat on backwards. The blower rotors will ‘screw’ the air toward the front, so the air is having to make a lot of turns with the hat backward.”

In early dyno runs the engine netted 2,012 horsepower. To date, driver Lee Warren has a best of 6.80 seconds at 180 mph is his boat.