The workmanship continues...
The workmanship continues into the combustion chambers, which are fully machined for precision in size and shape. Hemi heads allow for large valves, and their chambers make efficient use of the valve size (since as the valves open they move away from the cylinder wall, minimizing the effect of bore shrouding).
The Hemi valvetrain is complex...
The Hemi valvetrain is complex and elaborate compared to a wedge, and at high rpm only the finest components can deliver reliable service under roller cam loads. All the valvetrain components are Indy-manufactured pieces, and the valvetrain matches the Indy heads perfectly.
Another Indy-specific piece...
Another Indy-specific piece is their unique valley plate, which is sandwiched beneath the heads as they are installed. Access to the lifter valley is through a removable center hatch once the engine is assembled.
An Indy 426-3 intake manifold,...
An Indy 426-3 intake manifold, and a King Demon RS carb provide induction. The intake is far from the most radical offering made by Indy for the Hemi, but it is the lowest profile design. Hood clearance in the 'Cuda was the major consideration here. As builder Alan Johnson put it, "The last thing I want to have to do is put a big ugly scoop on the car." The RS carb can be adjusted from 795 cfm to 1295 cfm by swapping main venturi. Indy set the carb up at 1095 cfm for this application.
The intake manifold was fully...
The intake manifold was fully ported at Indy to enhance its airflow. It's surprising how many builders will neglect manifold flow even while heavily focused on cylinder head flow numbers. The experts at Indy realize that an airflow system is only as good as its weakest link. Builder Ken Lazzeri noted, "The intake had to be compromised some for hood clearance and overall height, but the porting made up quite a bit of ground."
Lighting the mix, Indy opted...
Lighting the mix, Indy opted for a complete MSD ignition system, including a crank trigger working in conjunction with a locked-out distributor, a Digital 7 box, an HVC coil, and a set of MSD wires. With a reputation of quality and reliability, there was no reason to look any further for ignition parts.
The crank trigger consists...
The crank trigger consists of a pick-up unit which is triggered when imbedded magnets pass a wheel mounted on the damper. Since the timing function is affected directly off the crank, the spark variation and scatter are eliminated. The conventional distributor is used solely to route the spark to the appropriate cylinder.
The signature item on a Hemi...
The signature item on a Hemi are those imposing valve covers, and these were engraved with both the signature logos of Indy and PHR, as we joined forces to create the g-Force version of Indy's 572 Legend Hemi. Indy builds bigger engines, but you'd be hard pressed to find a combo more willing to astound in open-road performance.
ON THE DYNO
How much power is enough, and just how much can our healthy g-Force Hemi deliver? The owner of the g-Force 'Cuda, Bob Johnson, looked at the extravagant output of the all-aluminum Hemi in an abstract way. Johnson relates, "The 'Cuda is not something we are putting together to conventional standards, not in looks, not in construction, and certainly not in performance. The car will push the limits, and then we'll shoot for a hell of a lot more, and that might just put us where we'd be satisfied." What does it take to be satisfied with the output of this metal warrior's powerplant? Five hundred and twenty pounds of aluminum dynamite, blasting the competition with 870 dyno-verified horsepower and a violent 780 lb-ft of torque should be enough to satisfy the most wanting power junkie's addiction.
Johnson pointed out that power was going to be key to the car's character, "You don't build a machine like this tube-framed terror and come up short on the punch line. You'd dammed well better have something special and it has to have the right power curve to do the job." Indy's chief engine builder Ken Lazzari massaged the combo for just that balance of output with the right curve. Lazzari explains, "Everything was keyed for meeting the goals of good street manners, and a power curve that comes on hard initially, but doesn't let go, pulling huge power up top to where the car will be able to really use it."
Lazzari continues, "We build engines that are significantly larger, but this displacement was selected for balance. We have so much torque down low the chassis guys will have a real job harnessing it at this level, so there isn't a need for more size and bottom-end. These heads at this displacement, with the rest of our combo, just keeps building power as the tach swings up. Get it in a street car and nail it, and you don't have to let go 'til over 7,000 rpm." A high-revving powerband that tastes like a Trans-Am small-block of yesterday, but scaled up to 572 ci of Hemi power, making double the power, and doing it tractably on pump gas. Indy's combo redefines g-Machine power.
DYNO CHARTINDY/PHR g-FORCE 572 HEMI
SUPERFLOW DYNO ACCELERATION TEST (600 RPM/SEC)
TESTED @ INDY CYLINDER HEAD
STP CORRECTION FACTOR
|* Denotes peak|
COMBOS TO CONSIDER
Indy's engine-building wizard, Ken Lazzeri, is in an enviable position. If your career is built on creating some of the nation's best engines, then what better home than Indy Cylinder Heads? What's the advantage? The definition of engine builder takes on a new twist at Indy since these guys actually manufacture the major components that make up the engines. Indy literally is in the business of building engines, with their own blocks, heads, intakes and more. Going to Indy for a custom or crate engine is like going to the source-a concept that couldn't be entertained when dealing with OEM factory components and building with an OE engine as a base. These parts are designed at a serious custom engine shop solely for the purpose of building serious custom engines for a variety of applications.
Lazzeri has the grab bag of specialty components at hand to build the right combo for the task at hand. For our g-Force Hemi, the constraints, which drove the selection of components for the build, included the targeted output, fuel requirement, drivability goals, and long-term durability. It helps that Indy has the hardware, and no one knows it better. Ken pointed out that other applications might benefit from other versions of their Legend-series Hemi.
As Ken puts it, "Our Hemi engines tipically displace between 5228-636 cubes with 605 being our most popular combo. We build quite a few 572s, and for this application that was the best choice, but for other applications the larger engines might be the right way to go. Ken notes, "The foundation based on our parts, and the bottom end, can take substantially more power. A blower could add 500 hp to the output of a package similar to this, while an engine with more cam and compression could clear an easy 1,100 hp or more. Other builds may benefit from fuel injection, depending upon the vehicle builder's wants. The street requirements of this build directed us to scale back the cubes, compression, cam, and port volume, basically turning what could be a race engine into a street piece you can drive around. Shrinking the package also works well for endurance, with less loading in aspects critical to engine life, like with valvesprings. This combo may seem like a monster when considering the raw power figures, but in fact, it's under-stressed, and the result is low maintenance and long engine life."
THE g-FORCE 'CUDA: BUILT TO DRIVE
Think all this engine voodoo is just some mental exercise? Think again. This Indy g-Force Hemi is born to run, and run it will. The car the g-Force Hemi will reside in was initially penned by Chris Ito of Ito Concepts (Dallas, Texas) and has some subtle-yet major-changes to the original '70 Cuda shape. Virtually every panel of sheetmetal will be cut, chopped, narrowed or otherwise pounded into submission to create the look for the g-Force 'Cuda. Below the surface, no stone will be left unturned. A set of custom Art Morrison frame rails will be home to a C5 Corvette suspension, and the g-Force Hemi will be set back and lowered for better weight distribution, a flat hood line and suspension clearance. A Getrag transaxle (which we previously and incorrectly identified as a C5 Corvette transaxle) will be housed in the rear for a truly world-class suspension. The finished product will debut at the 2005 SEMA show starting November 1, and PHR will have the exclusive story. After that, the 'Cuda hits the open road-as in "open road racing" and "setting the 0-100-0 world record for a street-legal car." We'll be there when it all happens, so stay tuned!