With its twin Ilmor Marine MV8 570 engines turning 6,000 rpm, a Formula 353 FASTech sportboat reached a top speed of 85.8 mph yesterday during testing, according to a report from the Decatur, Ind., boat builder. The 35-foot, stepped hull model is the first boat to be equipped and run with the 570-hp engines. (Read the story.)

Yesterday’s tests were conducted on Grand Lake St. Marys in Celina, Ohio. Weather conditions were 55 degrees with 85 percent humidity and 10- to 15-mph winds that produced 12- to 20-inch chop, according to the report.

“I wouldn’t say we’re at ‘final’ yet, but we’re pretty doggone happy,” said Scott Porter. Formula’s chief executive officer, in a telephone interview this morning. “We saw some great improvements from our early tests. We needed to make some adjustments.

With twin 570-hp engines from Ilmor Marine, a Formula 353 FASTech reportedly topped 85 mph in testng yesterday.

“Test conditions were ideal,” he added. “We didn’t pick yesterday for that—we were actually dodging thunderstorms—but they were perfect.”

Porter declined to elaborate on exactly what adjustments the Formula team made to the propulsion setup, but he did say that they included changing the X-dimension for the boat’s IMCO drives.

“I didn’t get to run the boat, but the guys said they were really, really pleased, especially with the engines’ acceleration,” said Porter.

Mounted on extension boxes, the drives were set up with 1.5:1 gear reductions and shorter lower units. Mercury Racing Maximus 15-1/4 x 25 five-blade propellers put the power to the water. Approximate test-time weight of the boat with 80 gallons of fuel, 15 gallons of water, 20 pounds of test gear and two test team members was 10,650 pounds.

At present Formula also is in the process of testing a 353 with twin Mercury Racing 565 engines. Porter declined to supply preliminary top speed numbers for that boat, but did say the numbers were comparable.

“We just want to optimize the Mercury installation before we let people know what it ran,” said Porter.

Editor’s Note: The Ilmor 570-powered Formula 353 will be on display next Thursday, April 25, during the Desert Storm Street Party in Lake Havasu City, Ariz.

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