If there’s a universal truth about motorsports, it’s that no matter how quick a machine is, it’s only a matter of time until we’re searching for ways to take it to the next level. Keith Rhea is certainly no exception to that rule.
As the owner and operator of Wonder Racing in Derry, PA, Rhea is in the business of hauling ass, so it comes as no surprise that when he took delivery of a low mileage race-prepped SN95 in the fall of 2015, it merely served as a foundation for Rhea and Wondering Racing to get started building their vision for the car.
When Rhea took delivery of this 2004 Mustang Cobra in September of 2015 it was already a fairly stout performer by most enthusiasts’ standards. With just over 14,000 miles on the clock, the Cobra’s factory powerplant had been warmed over, and a 3.4-liter Whipple was on board to provide boost. But within a month, Rhea and the crew at Wonder Racing had already tossed the blower in favor a twin turbo setup, initially starting with a pair of Precision 6266 units. It would be the first of several different setups that the Mustang would see over the next year and a half as the team continued to make the car quicker and quicker - an effort which is ongoing as they prep for the 2018 season.
“The previous owner had a ten-point rollcage and a built engine with a 3.4-liter Whipple supercharger in it,” he recalls. “By October, the blower was gone, replaced by a pair of Precision 6266 turbos.”
This would prove to only be the beginning of a series of increasingly more radical upgrades that Wonder Racing would do to this 2004 Mustang Cobra over the following months, modifications that would turn an already quick car into bonafide drag strip monster. But like any endeavor worth pursuing, this project’s journey hasn’t been without a few speed bumps along the way.
The Path To Seven Seconds
Not long after swapping out the Whipple blower for a pair of Precision turbochargers, Rhea decided to dial things up even further. He ditched that motor and the Precision 6266s in favor of a big-bore 5.3-liter mod motor and a pair of Precision 7275 snails, a combination that Rhea says was good for about 1,400-horsepower at the wheels.
From a glance, the Mustang’s bodywork looks pretty close to the stock Terminator-era Cobra kit, but there are a few strategic mods going on here as well. Along with the hood cut-out, Innovative Racecraft rear wing, and Pro-Fab carbon doors, the custom headers from CG Fabrication exit directly through the fenders to keep things simple and lightweight.
That might be enough for some racers, but Rhea and the Wonder Racing team weren’t satisfied for long. “I ran this setup for about five or six months before I decided to make the change to a 5.4.-liter GT500 aluminum block,” he explains.
After switching to turbocharged setup, then upgrading said turbos, Rhea says the car was making roughly 1,400-horsepower at the wheels on the motor he bought the car with. But after half a year of that the Wonder Racing team was ready to step things up again, replacing that mill with an aluminum 5.4-liter block from a fifth generation GT500.
“This setup went 7.99 at Bowling Green NMRA in 2016. Unfortunately, we popped a coolant hose on the next run, which sent the car sideways at 170 mph, and we bumped the wall.”
The stout bottom end consists of a Winberg billet steel crankshaft, Manley 300m I-beam connecting rods, and custom-spec Diamond pistons. Considering the plans the team has for the forced induction setup in 2018, this investment in durability will likely prove to be well worth the effort.
While the damage was fairly minimal considering the circumstances, Rhea decided to rebuild the car from the ground up that winter anyway, once again dialing the project up a notch or two in the process.
Helping Wonder Racing achieve that 1.12 60′ time is a set of custom Menscer Motorsports canister shocks paired up with Afco springs, and Racecraft Inc. supplies the Mustang’s upper and lower control arms. Up front Afco springs are matched up with Viking Performance struts, while the A-arms and K member come from Team Z.
The 2017 Setup
As it stands, now the 333-cube mill sports a Winberg billet steel crankshaft, Manley 300m rods, and custom-spec Diamond pistons with Total Seal rings on the bottom end, while custom Crowler billet camshafts, a custom Hogan Racing intake with an Accufab throttle body and Fox Lake cylinder heads round out the combination up top, where factory GT500 rocker arms and lifters are matched up with Crower valve springs.
The power plant is fed by way of a cable-driven mechanical fuel pump from Waterman Racing, which sends the juice through custom Hogan fuel rails to a set of Billet Atomizer injectors. A Holley Dominator EFI system controls the proceedings and uses an in-house built harness as well as custom tuning done by Wonder Racing team.
With the Precision 7275 turbos on board for the 2017 race season, Rhea says they ran max boost pressure of 33 psi, and they expect that number to be bumped up to 40 for this coming season. Up front a custom air to water intercooler built in-house by Wonder Racing helps keep IATs low. Power is sent to the ground through an 8.8 rear end that was built in-house as well, with 4.10 gears used on eighth-mile tracks while a 3.55 is on hand for quarter mile racing.
Paired up with those Precision 7275 turbos, the grunt is sent to the rear wheels through a Powerglide gearbox, then to a custom 8.8-inch rearend with 35-spline Moser axles and 3.55 gears.
As you might expect, the chassis has seen its fair share of attention as well. Up front, the K-member and A-arms are from Team Z Motorsports, while Afco supplies the springs that are paired up with Viking Performance struts. Out back, Rhea is using Racecraft upper and lower control arms, Afco springs, and Menscer shocks. The power gets to the ground through a set of Billet Specialties beadlock wheels wrapped in 275mm-wide Mickey Thompson Radial Pro rubber.
While Rhea took delivery of the car already in fighting shape, over the past two years, he and the team at Wonder Racing have built progressively more potent setups for the Mustang as they chipped away at its E/Ts. They broke the 7-second quarter mile barrier back in 2016 after building the 5.4-liter motor for the car, but an unplanned meeting with the retaining wall on a subsequent run would inspire the team to rebuild the car from the ground up between the 2016 and 2017 race seasons. The car would post a 7.48-second pass the first time off the trailer last season and would continue to knock out low seven-second passes for the rest of the season.
Rhea also explains that, due to issues with the Fox Lake-prepared heads they ended up using a set from MMR during the 2017 season, but it doesn’t sound like it slowed Wonder Racing’s SN95 all that much. “We came out swinging last season, going 7.50 right off the trailer at Bowling Green NMRA, then winning King of the Hill there,” he tells us. “Next was the World Cup Finals, where we qualified 12th in a strong field and went on to run a personal best of 7.17 @ 195 mph with a 1.12-second 60-foot time.”
The team wasn’t done there, and went on to win the ModNationals’ King of the 4-Valve event before wrapping up the season.
After taking home the King of the Hill title at Bowling Green NMRA as well as King of the 4-Valve at ModNationals in 2017, Wonder Racing has proven to be a formidable competitor in every race class they compete in. With a new set of cylinder heads as well as a pair of larger Garrett turbos in store for 2018, the team is looking to step things up even further, and hopes break into six-second territory in the upcoming season.
As for 2018, it should come as no surprise that Rhea and Wonder Racing have a few upgrades planned for the Mustang for the upcoming season as well. Along with adding the Fox Lake-prepared cylinder heads to the mix, Rhea is looking to squeeze some more power out of the forced induction setup by swapping out the Precision 7275 turbos for twin Garrett 8087s, and along with the upgrades comes a new performance target for 2018. “6.80 at 205 should be achievable with this combination,” says Rhea. “That’s the goal for this year.”