Standard engine building techniques are utilized when assembling a late-model Hemi, and we tightened the head studs in three sequential steps to a final torque of 100 lb-ft. With the heads in place, it was time to concentrate on our intake manifold, which also means addressing the ignition system of our engine. Since all late-model Hemis lack a distributor or a provision for a distributor, the ignition system must be controlled by a computer attached to individual coil packs for each cylinder. Indy Cylinder Head has come up with a great way to incorporate the coils under the intake manifold, using plug wires for the spark plugs just like the first and second generation Hemi engines.

We're utilizing a Mopar Performance Drag Pack intake manifold on our 426 Hemi, and the crew at Indy machined provisions in the bottom of the intake so that the eight individual coil packs could be bolted underneath using one of their coil plates. Using a Hemi-6 programmable controller, wiring harness, and coils from MSD, along with plug wires from Indy Cylinder Head, this technique allows for a much cleaner, somewhat nostalgic look for the late-model Hemi. The MSD ignition box also allows the ignition to be run as a stand-alone system, without the complexity of fuel injection. The Hemi-6 controller is easily programmed with a laptop computer, and the harness plugs right into the factory crank and cam sensors, as well as the coolant temp and MAP (manifold air pressure) sensor.

What this means for old-school tuners, is that the late model Hemi can be used with a carburetor, just like the first and second generation versions. And while we certainly aren't opposed to fuel injection on our street cars or even a race car, running a carburetor on our dedicated bracket racer will make things easier in terms of wiring, fuel system plumbing, and overall simplicity. To top our Mopar Performance single-plane intake, we decided to test two different Holley Ultra-HP carburetors, an 850-cfm and a 950-cfm version. We've had great luck with these new Holley carbs since they came out, finding them to be very accurate right out of the box. The Ultra HP carbs also offer some great convenience options like a drain plug for each float bowl, making tuning even easier than previous Holly carbs.

Once we had our engine complete, we bolted it to the dyno and connected a set of tti headers to find out how our combination would perform. The headers we're using are tti's Drag-Pack units, featuring 17⁄8-inch primary tubes stepped up to 2 inches, with 3-inch to 4-inch tapered collectors. These headers will also be installed in our '10 Challenger once we get the engine in the car.

Running on 92 octane pump gas, from the station right up Southeastern Avenue from Indy's shop, we fired up our Hemi for some break in time and dyno pulls. The Comp hydraulic roller cam in this engine has a fairly wide 114-degree lobe separation, and combined with 10.85:1 compression our Hemi had a fairly smooth idle and sounded pretty docile when running at low rpm. We had some pretty good expectations for this engine, but our Hemi certainly didn't have the idle quality or cackle of a high-powered race engine. Once the throttle opened, however, this late-model Hemi came to life.

Making a couple of short pulls to help seat the rings, we were impressed when our power numbers already topped 600. Comfortable that our engine was sound and properly broken in, we quickly programmed the MSD Hemi-6 ignition controller for 13 degrees of total ignition timing. With the 850 Holley carb, horsepower was tickling the 700hp range, so we decided to see if this engine wanted more fuel and air. Swapping from the 850 to the 950-cfm Holley Ultra HP, we made a full pull on the engine to 7,000 rpm. When the dyno numbers appeared on the computer screen we weren't just impressed, we were astounded. By race engine standards this is a fairly mild combination, running on pump gas, and it made well over 700 horsepower. With a single jet change, we achieved an amazing 719.5 horsepower at 7,000 rpm, and 605 lb-ft of torque at 5,300 rpm.

Having built many Mopar big-blocks, small-blocks, and early Hemi engines, we can say that without a doubt this late-model Hemi produces more power with a milder combination than any other Mopar V-8. The power and torque numbers we achieved from this engine are real race engine numbers, without the huge displacement, high compression, or aggressive solid roller cam that most race engines require to make this kind of power. If any of our readers weren't sure about the late-model Hemi, we encourage you to carefully review the specs of this engine. In our opinion, this is the best platform available for a Mopar engine build, whether for a late-model car or an earlier Mopar. We can't wait to get this engine into our Challenger and hit the track, so be sure to watch future issues of Mopar Muscle to see what kind of numbers we run.

Price Tag
6.4 late-model Hemi heads $1200.00
Indy preparation and cnc porting $1080.00
Holley Ultra HP 950 Carburetor $810.00
Mopar Drag Pack intake manifold $1039.99
MSD Hemi Six ignition box $474.95
MSD Hemi Six wiring harness $185.95
MSD coils $442.95
TTI late-model Hemi headers $740.00

SOURCE
Milodon
2250 Agate Ct.
Simi Valley
CA  93065
805-577-5950
www.milodon.net
Indy Cylinder Head
8621 Southeastern Ave
Indianapolis
IN  46239
317-862-3724
www.indyheads.com
Autotronic Controls MSD Ignition
1490 Henry Brennan Dr.
El Paso
TX  79936
www.msdignition.com
Holley
1801 Russellville Road
Bowling Green
KY  42101
270-781-9741
www.holley.com
Callies Performance Products
901 South Union St
Fostoria
OH  44830
419-435-2711
www.callies.com
Meziere
800-208-1755
meziere.com
Diamond Pistons
23003 Diamond Drive
Clinton Township
MI  48035
877-552-2112
www.diamondracing.net
ATI
Baltimore
MD
800-298-5039
ATIRacing.com
tti Tube Technologies
1555 Consumer Circle
Corona
CA  92880
909-371-4878
909-371-6143
ARP Racing
531 Spectrum Cir., Dept. EM
Oxnard
CA  93030
Comp Cams
3406 Democrat Rd
Memphis
TN  38118
800-999-0853
www.compcams.com