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g-Force Hemi

Indy builds an all-aluminum 572 that redefines the g-Machine powerplant
From the February, 2009 issue of Popular Hot Rodding
By Steve Dulcich
Photography by Ken Lazzeri
0505Phr Hemi 01 Z
We were asking a lot when... 
   
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0505Phr Hemi 01 Z
We were asking a lot when we approached Indy to build the ultimate g-Machine engine. Just make it a Hemi, only about 150 cubes bigger than a stocker, but make it weigh less than a small-block. Make power like a serious drag motor, and make it run smooth and reliably on the street in full-out open-road race competition, on pump gas, please. Easy, huh?
0505Phr Hemi 02 Z
The backbone of our Indy-built... 
   
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0505Phr Hemi 02 Z
The backbone of our Indy-built g-Force 572 is an Indy 10.720-inch deck aluminum Hemi Maxx block. With a capacity to easily accept a 4.50-inch bore and the weight savings of aluminum, the Indy block is the basis for huge power in a lightweight package, just the one-two punch we needed for our ultimate g-Machine mill. The Maxx blocks are fully CNC machined at Indy from a bare casting of Indy's design.
0505Phr Hemi 03 Z
The block's finished bore... 
   
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0505Phr Hemi 03 Z
The block's finished bore size of 4.50 inches is matched with a 4.50-inch stroke Callies 4340 forged steel crankshaft. The rod journals are undersized at a big-block Chevy spec of 2.20 inches, reducing bearing speed and increasing stroke clearance in the crankcase. The Eagle 3D connecting rods measure 7.10 inches and are sized for the Chevy 2.20-inch crankpin, and likewise accept a 0.990-inch Chevy big-block piston pin at the small end. Pistons are Wiseco small-dome forgings as spec'd by Indy, and weigh-in at 755 grams. The combo provides a rod ratio of 1.58:1, very reasonable for such a long-armed crank-got to love that tall block deck that makes it possible.
0505Phr Hemi 04 Z
Taking advantage of coating... 
   
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0505Phr Hemi 04 Z
Taking advantage of coating technology, the pistons for this build were sent to the experts at Swain Technology for thermal barrier coating of the crown, and an anti-friction coating to the skirts. Hemi engines have considerable piston surface area which presents a challenge to thermal inefficiency. The thermal barrier helps retain combustion heat with the goal of adding power through greater efficiency. By the same token, stroker engines will present greater thrust loading and rod angles than short-stroke engines. Friction-coated skirts help put the slip to friction at the source.
0505Phr Hemi 05 Z
Note the deep intake valve... 
   
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0505Phr Hemi 05 Z
Note the deep intake valve relief and low top ring placement of the piston. Indy has these packages worked out to a science, and the considerations in putting together a working combo are pretty complex. If you're building a monster Hemi on your own, you better be prepared to work out all of these detail, like ring placement, dome height, valve relief depth, location, and a lot more. Trying to get it right on a one-off custom build can be pretty tough, or you can skip the guesswork, trial and error, and let Indy's experience with these combos work for you.
0505Phr Hemi 06 Z
If serous power output is... 
   
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0505Phr Hemi 06 Z
If serous power output is the goal and keeping it together is also part of the plan, you simply cannot go slummin' in the maincaps. Big strokes, high rpm, and big power and torque brutalize the bottom end. Stock Mopars will walk the maincaps at moderate power levels. These Indy blocks are designed with integrated billet steel maincaps in mind. The cross-bolted caps tie the entire lower structure of the block into a "bridge" which, combined with the massive lower-block bulkheads, provides an anvil-tough structure. Cross bolting eliminates the cantilevered structure of a standard-style cap, and is possible only in a deeply skirted block as in a Mopar Hemi or Wedge.
0505Phr Hemi 07 Z
With the crank and mains installed,... 
   
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0505Phr Hemi 07 Z
With the crank and mains installed, it's easy to see how the structure of the lower block is securely tied together. Note the stroker clearancing done to the lower cylinder walls in the crankcase. Indy has worked out the programs for their popular applications making the clearancing a routine and foolproof CNC operation.
0505Phr Hemi 08 Z
Indy's Maxx block is fully... 
   
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0505Phr Hemi 08 Z
Indy's Maxx block is fully water jacketed, and designed for both street and race applications. The cylinder walls are centrifugal-cast sleeves, which are a dry-sleeve configuration in the block. This provides the best in bore stability, rigidity of the decks, and reliability in long-term operation. Notice also the beefy ribbed lifter valley and high-strength Indy-sourced head studs. Get the idea that the guys at Indy aren't fooling around? The engineering is first-rate.
0505Phr Hemi 10 Z
Driving the camshaft is an... 
   
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0505Phr Hemi 10 Z
Driving the camshaft is an Indy Rollmaster billet gear timing set. With the roller cam, thrust must be controlled to keep the cam located properly in the block, a task accomplished with a thrust button clearanced to work with Indy's No. 440-22 aluminum timing cover. Also, at the front of the engine Indy employs a premium ATI Super Damper, No. 917475 E, regarded as one of the most effective in the industry at controlling crank harmonics.
0505Phr Hemi 09 Z
The camshaft is a Comp No.... 
   
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0505Phr Hemi 09 Z
The camshaft is a Comp No. CRH 300-7-295-4 R110 (measuring 268/264 at 0.050-inch and with 0.650/0.630-inch lift), may seem "big," but with 572 ci soaking it up, the combination is more than docile enough to work well on the street. Engine builder Ken Lazzeri considers it "mild"-and it is, compared to the full-race combos put together by Indy. Ken described the idle as "smooth." The roller lifters are Comp No. 829-16, while the springs are Comp No. 26115-16, delivering 210 pounds of load at 2.10 inch. The tall installed height, and moderate spring loads provide longevity and control. Comp titanium retainers help lighten the weight load at the valve, and are 10-degree units for use with Comp's 10-degree SuperLocks.
0505Phr Hemi 11 Z
Ken precisely degrees-in the... 
   
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0505Phr Hemi 11 Z
Ken precisely degrees-in the cam in every engine Indy builds. For this engine, the camshaft was phased at 105 degrees installed intake centerline, which is 5 degrees advanced with the camshaft ground on a 110-degree lobe separation angle. With an installed intake centerline of 105 degrees, and the shorter exhaust lobe, exhaust overlap is reduced and trapping efficiency is enhanced, helping to further tame the large stick.
0505Phr Hemi 12 Z
With the cam timed in place,... 
   
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0505Phr Hemi 12 Z
With the cam timed in place, Ken moves on to installing the pistons. The rings, No. R10451-45, have already been sized to the bore for an end-gap of 0.024-inch top, 0.028-inch second. This is in keeping with modern ring theory on ring end-gaps, opening the second gap larger than the top to reduce the chance of ring unloading due to trapped pressure in the ring pack between the compression rings. A tapered ring compressor allows the piston assembly to slide into the block with a minimum of persuasion, and is a tool worth having.
0505Phr Hemi 13 Z
With the g-Machine aspirations... 
   
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0505Phr Hemi 13 Z
With the g-Machine aspirations of this engine build, the sump and lubrication system had to meet some specific requirements. Oil control under acceleration, braking and cornering were vital, while reducing windage losses and controlling the oil were also important considerations. Under road-race style demands, nothing will compare with a dry-sump system so that was the system selected for our g-Force Hemi. The four-stage gear-driven Missile dry sump pump system is a thing of beauty, operating in the Hemi application without the need for cogged drive belts as with most dry-sump applications. The Charlie's dry-sump pan offers excellent windage control and a much lower profile than a deep wet-sump pan. This will be a big aid in getting the engine set as low as possible in the chassis, benefiting ground clearance as well as allowing a lower center of gravity.
0505Phr Hemi 14 Z
The Indy-manufactured aluminum... 
   
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0505Phr Hemi 14 Z
The Indy-manufactured aluminum block provides the foundation for this engine, and the Indy cylinder heads open the potential for the bottom-end to develop huge power. As with the blocks, the heads are Indy's own castings and are machined in-house on precise CNC equipment. The heads for our build are Indy's Legend, part No. 426-1 RA.
0505Phr Hemi 15 Z
Indy's Windjammer cylinder... 
   
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0505Phr Hemi 15 Z
Indy's Windjammer cylinder head porting is also done via an automated CNC program and the results are impressive. Intake port flow pegs the scale at 510 cfm, with an intake port volume of 295 cc. Intake port volume is critical to power production and keeping up with demand as rpm rises. A combination of high-flow and sufficient port volume is what it takes to extend torque production up the rev range, and really making use of the power output a large displacement engine can develop.
0505Phr Hemi 16 Z
Looking down the cavernous... 
   
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0505Phr Hemi 16 Z
Looking down the cavernous intake ports, there is little in the way of moving copious quantities of air directly into the cylinder. Intake valves measure 2.40 inch, while the exhausts measure 1.940 inch.

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