g-Force Hemi

Some guys just have a driving ambition for the one-upmanship and achievement in building "The ultimate" g-Machine. When you consider it, it's a tall order. In the realm of street performance, the goal of the g-Machine has "the ultimate" wrapped up in it by definition. Unsurpassed handling, roadabilty, acceleration and balls-out power are the hallmarks of the g-Machine scene. Attempting to render the ultimate incarnation of the g-Machine is really striving for the ultimate of the ultimate. Bob Johnson is driven towards this goal, and has expressed that ambition through some serious g-Machine project vehicles in the past. His previous efforts have been featured and acknowledged in these pages. (See Bob's '69 Camaro called "Battle Axe," in Jan '04. It was our cover car that month.) Bob's latest endeavor lead to what may be the Holy Grail of the Mopar g-Machine: interpreting Mopar's most desirable musclecar body style, the 'Cuda, as the ultimate g-Machine. Bob teamed up with car builder Alan Johnson (no relation) to craft the concept into reality. The team of Johnson and Johnson were looking towards pushing the envelope far beyond the normal consumer goods, taking their crack at the "The ultimate g-Machine." The finished vehicle will be featured in PHR as an exclusive once it's completed, but those wanting a sneak peak will be able to check it out at the 2005 SEMA show in Las Vegas Starting November 1. Be Forewarned: Don't expect it to be a pampered show car. Bob Johnson's g-Force 'Cuda will be driven hard-hard enough, we expect, to set a new record for a street car going from 0 to 100, and back to 0. That takes a lot of gs (in more ways than one).

Function, form, and most importantly true performance, all integrate into a project this ambitious. Alan's Art Morrison-based chassis will debut with significant engineering, from the custom tube chassis, and one-off all independent coil-over sprung suspension, Baer six-piston disc braking system, massive Michelin PS2 tires, and custom Getrag transaxle. No stone will be left unturned in incorporating the hardware to meet their goals. Of course, topping the list of required machinery for a project of this sort is a suitable powerplant. For this Mopar, Indy Cylinder Heads was the natural choice.

Indy Cylinder Heads (ICH) is a name well known to Mopar fanatics the world over. No one has taken the mantle of Mopar engine performance and gone the distance in the way the organization at ICH has. A milestone for ICH founders Russ and Fred Flagle, was a pioneering move into aftermarket aluminum heads for the Mopar wedge engine introduced decades ago. From this, Indy has grown to design and manufacture Wedge, and Hemi engine components that define contemporary Mopar performance. Indy manufactures blocks, intakes, heads, and many more components that propel the original Mopar engine architecture to power levels, and configurations unheard of back in the original musclecar days.

For the Johnsons' project, the Hemi engine would provide the presence and persona of pure power that would help define the 'Cuda. Hemis are no strangers to power production, but in a g-Machine application the sheer mass of the engine would disturb the delicate balance that the builder was looking to achieve with the vehicle. Here, ICH provides the answer in their aluminum Maxx block. Using the Maxx as the basis for the powerplant opens the door to a near ideal situation. Indy's complete all-aluminum Hemi makes for a lightweight package, tipping the scales at a small-block-like 535 pounds. Low mass is nice, but the powerplant is advantaged further by the sheer strength and capacity possible with the Indy Maxx block. Indy can, and routinely does, build these engines in displacements of 655 plus ci, and the power handling capacity are off the scale. Indy's hardware makes the notion of a lightweight, big inch, high-powered and reliable Mopar engine a reality.

But the high-g nature of Indy's g-Force Hemi doesn't end with lightweight. In order to achieve the ultimate balance for handling, car builder Alan Johnson made the decision to position the Hemi rearward and lower in the engine compartment, thus setting into motion some rather significant design requirements for the engine, body, and drivetrain. Rearward location of the g-Force Hemi meant using the aforementioned Getrag rear transaxle, but it also meant using a dry-sump oiling system. This allows for superior oil scavenging under hard cornering loads, and it also improves the vehicle's center of gravity by allowing the engine to be much lower in the chassis. Yes, it sounds odd, but the Indy g-Force Hemi is an engine that-when integrated properly with the chassis-actually improves handling.

Zeroing in on the exact combination for this project was a collaborative effort with input from the vehicle builder providing the objectives that needed to be met. Making more than a useable amount of power would be no problem based on the resources at Indy, however the Johnsons imposed constraints. The engine would above all need to meet the requirement of real streetabilty. This is defined by the requirements for reliability in long-term street use, a reasonable, if not tame idle quality, and the ability to swill normal pump gasoline without balking (although just barely!). With the massive reserves of power potential in the Indy Legend line of aftermarket Hemis, meeting these goals, while producing unnerving output was the task of Indy's chief engine builder Ken Lazzeri.

Ken took the "conservative" approach, knowing that by scaling back the combo of one of Indy's race-spec'd mills, the drivability, low-maintenance and reliability objectives could be easily met. At the same time, with a relatively large displacement and just enough cam, compression and cylinder head, the output would remain dramatic. Although the engine, with a bore and stroke of 4.50 inches displaces 572 ci, by Indy's standards this is a conservative displacement. In a street application, it would be hard to argue that 572 cubes would fall short of delivering all the torque a car could manage. Low-end torque is what you'd expect, but what comes as a surprise is the high rpm characteristics of this mighty Hemi. Power just keeps coming on, a testimony to the outstanding matching of the combination's components, and the phenomenal flow of Indy's Windjammer CNC-ported heads. The bottom line: what we have here is a 572ci Hemi that weighs-in and revs like a small-block, while belting out more torque and power than most street freaks could imagine. If like Alan and Bob Johnson, you are looking to build up the ultimate, here in detail is what Indy did to make it come together.