Let's pretend for a minute that, instead of being a cubicle-dwelling 9-to-5 working man (like most of us), you were actually fortunate enough to be the owner of one of the most high-profile transmission shops in the country. Now, let's try to forget about all of the hard work, long hours, and stress that such a job actually consists of and instead focus on living the dream, owning cool cars and having the time to install goodies and test them out all in the name of "research and development." Believe it or not, such an awesome life actually does exist and the man at the top of this particular empire is none other than Rodney Massengale, owner of RPM Transmissions (RPM) in Daleville, Indiana. Now, if you talk to Rodney, TJ, or any of the highly talented guys at RPM, they may tell you a much different version of this dream but we're going to run with the assumption that providing parts for some of the fastest LS-powered race and street cars in the country, while also getting to test them on your project cars, isn't a terrible way to make a living. Sure, some may call it "product development" but to others, like us, even getting a chance to spend time around a 9-second C6 Z06 is the stuff dreams are made of.
For Rodney and his crew, racing his personal Z06 is, quite literally, just another day at the office, taking on hyper-powerful cars and proving that reliable overdrive transmissions can and will live under racing conditions if properly built. According to TJ, "We built this car to showcase our 4L65E conversion. It shows how easy the car is to drive and how well it runs at the track. The car is very smooth and clean due to the automatic conversion and stock cam. Your grandmother could drive this car!" Yes, you read that right, this Z06 has been converted to a 4L65E automatic transmission, which we understand won't enamor the die-hard manual transmission guys, but bear with us for a minute. Once you understand more about this ride, the advantages of this conversion will become very obvious.
First off, let's discuss the engine combination. "The car has a completely stock [LS7] engine, never even had the valve covers off!" OK, well that was easy. Moving forward in the engine bay, we have the real secret to the horsepower, a Procharger D-1SC supercharger system that has been tweaked to work flawlessly run after run. For maximum boost, RPM installed a Cartek flip drive and 8-rib Innovators West crank damper, which brings boost in at 15 psi, enough air to lay down over 689-rear-wheel horsepower. Helping expel all of that air, Rodney relies on a set of Kooks 2-inch long-tube headers, which feed a 3-inch X-pipe and a set of B&B bullet mufflers. And, that's it for power.
Behind the basically stock LS7 is where the real trick stuff begins, starting with a Driveshaft Shop prop shaft, which smoothly delivers torque to a custom-built 10-inch Coan 3,600-stall converter. Behind the converter sits the entire reason this build even began, the RPM Transmissions Level 7 4L65E automatic transmission. Built with the best parts RPM could find, the Level 7 4L65E features an extra-wide, heavy-duty double-caged 29-element sprag, an upgraded 2.85 First gear planetary, billet Second and Fourth gear servos, 300M hardened input and output shafts, a Transgo shift kit, an SFI approved bellhousing, and micropolished internals. With that much internal hardware, you can see why it deserves an entire car built around it. Of course, the transmission and upgraded prop shaft mean nothing without a stout rearend and here again, Rodney worked in house to build a C6 ZR1 rear, which houses a Quaife torque biasing differential, a set of 3.42 micropolished gears and a pair of The Drive Shaft Shop 300M axles.
Further outboard, Rodney installed a pair of 18x13 CCW Corsair wheels, which are wrapped in a set of massive 345/35/18 M&H drag radials. To help his drivetrain parts shine, Rodney turned to another well respected shop, Pfadt Racing, to supply him with a set of Pfadt Racing coilovers, sprung by a set of custom drag race springs designed by RPM. Out back, Rodney runs a Pfadt competition adjustable sway bar, which works in conjunction with the rest of the package to help deliver consistent mid-1.3-second 60-foot times. And if those wicked 60-foot times don't impress you, consider for a moment that they help propel this Z06 consistently into the 9.6-second zone at over 143 mph. And when we say consistently, we mean over 75 passes since it was built, without having a single failure or mechanical issue.
Outside, as well as in, the RPM Z06 remains almost completely stock, with the exception of the CCW wheels and a custom cowl hood, which was painted to match the Velocity Yellow factory paint. To safely run at the track, RPM installed a Pfadt Racing rollbar with custom swing-out door bars. One interesting item, although probably mostly overlooked, is the use of an '05 factory automatic center console and shifter, which acts as a subtle reminder that this Z06 is much more than meets the eye.
So, what's next for this rolling testbed? "We're going to put in a much bigger motor and see what, if anything, needs more work in the drivetrain." Like we said, Rodney and the crew at RPM are serious about making sure they keep pushing the envelope and finding the limits of their parts. And when they talk about "the limits" they plan on finding them with a Warhawk block, a fully forged rotating assembly, All-Pro/WCCH cylinder heads, and a Procharger F1-R head unit. Like we said earlier, it's a tough job to track and street test all of these parts, but somebody's got to do it!
Car: 2007 Corvette Z06
Owner: Rodney Massengale
Block: LS7, 427 cid
Compression ratio: 11.0:1
Heads: Stock LS7, 2.20 intake, 1.61 exhaust valves
Cam: Stock hydraulic roller, 211/230 duration, 0.591/0.591-inch lift
Rocker arms: Stock, 1.8-ratio
Pistons: Stock, hypereutectic
Crankshaft: Stock, forged
Rods: Stock, titanium
Throttle body: Stock 90mm, ported by RPM Transmissions
Fuel injectors: 60 lb/hr
Fuel pump: Stock in-tank, Kenne Bell Boost-A-Pump
Ignition: Stock coil-near-plug, NGK TR6
Engine management: Stock ECM, tuned by Phil Hoeffler
Power-adder: ProCharger D-1SC
Boost: 15 psi
Bypass Valve: ProCharger Race
Intercooler: ProCharger air-to-air
Exhaust system: Kooks 2-inch long-tube headers, X-pipe, B&B mufflers
Transmission: 4L65E, built by RPM Transmissions
Torque Converter: Coan 3,600-stall
Driveshaft: The Driveshaft Shop
Front suspension: Pfadt coilovers, stock control arms, no sway bar
Rear suspension: Pfadt coilovers, stock control arms, Pfadt sway bar
Rearend: ZR1 IRS, 3.42 gear, 300M Drive Shaft Shop axles, Quaife posi
Brakes: Brembo Gran Turismo 15-inch front, 14-inch rear
Wheels: CCW Corsair 18x4 front, 18x13 rear
Front tires: M&H 185/50/18
Rear tires: M&H 345/35/18
Fuel octane: 100
Best ET/MPH: 9.60/143
Best 60-FT Time: 1.36