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Duttweiler Shoots for 450 MPH With LS Engine at Bonneville

Marlan Davis Jun 20, 2017
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George Poteet's Speed Demon blown Fuel streamliner, the world's fastest piston-engine-powered land vehicle as certified by the FIA, will be back at Bonneville this summer running a totally new turbocharged, 441ci, LS-based engine combination built up around Dart's Gen-III LS Next compacted-graphite-iron race block and its aluminum Race Series 10-degree LS canted-valve heads. Engine builder and crew chief Ken Duttweiler explains the reasons for the switch from the car's previous record-holding, small-displacement, Gen-I style small-block: "We wanted to move up to the 'big-block' streamliner class to go even faster and set yet another new class record, but the chassis isn't wide enough. Dart's new LS block is available with a 9.300-inch deck-height, which allows us room for a 4-inch-stroke crank. The tallest Gen-I race block is only 9.300 inches. We special-ordered the new block with Ford Cleveland-sized, 2.75-inch-od, main journals that allow a crank with plenty of journal overlap for supporting the power-level we'll be making. Our engine will be 441 ci in a class that permits up to 500 ci—essentially, a big-block wrapped in a small-block envelope." Duttweiler says the new architecture has the potential to eventually make 3,000 hp, "but right now 2,3002,400 is all we need to pump our current FIA 438-mph two-way record with the old-style small-block another 20 mph." When we recently stopped by the shop, the new Dart heads had just arrived. Check out the photos and video.

01 Dart LS Head Intake Ports 2/7

The Dart LS splayed-valve heads have symmetrical intake ports, unlike the previous-gen Dart splayed valve heads formerly run by Duttweiler on his Gen-I style small blocks. "I expect to see 460470-cfm flow-numbers from the 368cc intake runners."

02 Dart Little Chief Vs LS Race Head Chamber 3/7

The heart-shaped chambers on both the Dart Gen-I (left) and LS (right) are nearly identical. They use 2.300-inch intake valves—that's big-block territory.

03 Ken Duttweiler 4/7

Ken Duttweiler is shooting for a 450-mph two-way average speed with his new LS-based 441ci engine combo.


Dart Machinery Ltd.; Troy, MI; 248.362.1188; DartHeads.com
Duttweiler Performance; Saticoy, CA; (805) 659-3648; kduttweiler@earthlink.net



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