Cory went to TPI Specialties and Cottrell Racing Engines in Chaska, Minnesota, to get the 427ci LS-1 built after an over-revving accident at the track. Ryan followed suit after a heads and cam swap didn't deliver the power he was looking for.
The block in Cory's car is bored 4.060 inches and holds a 4.125-stroke Lunati crank and a TPI Specialties cam with 0.629 inches of lift and 251-degrees duration at 0.050 inches of lift. TPI Specialties-ported LS-1 heads and an LS-6 intake with oval ports sit atop the block.
Ryan's motor is nearly identical, but was built to make 11.5:1 compression to Cory's 12.1:1. It also features a TNT Stage 1 nitrous kit jetted for a 150hp shot. Cory and Ryan made many other modifications to their cars including suspension and exhaust upgrades and interior restoration.
The Corvettes were built as pump gas cars, but the fuel of choice changed in the summer of 2006 when friend Andy Wicks, owner of DynoTune Mobile Chassis Dyno Service in Watertown, South Dakota, asked to use the cars as guinea pigs for a flex-fuel tune. Cory and Ryan didn't hesitate to agree. "He said he'd done his research and having taken them completely apart as much as we have-I mean we've had them completely gutted, both subframes dropped, we've had them torn apart to nothing-we knew if anything did happen, we could fix it," Cory said.
They didn't have to fix anything. With little more than software and the addition of 60-pound injectors, Wicks made a complete flex-fuel conversion. A little more than a year later, with no changes to engine seals and using stock fuel lines, the cars are still running great.
"The corrosion stuff everyone worries about is pretty much nonexistent," said Wicks, who now sells handheld flex-fuel tuners for late-model Corvettes for $450.
Cory and Ryan said they haven't experienced any problems. The biggest advantage is the elimination of detonation, which was a problem when using pump gas in the high-compression motors. "You really get more power out of it," Ryan said. "It wouldn't detonate like on a pump gas, so you can push the envelope a little bit more."