It used to take big cubic inches to make big power. In fact, at one point in time, one horsepower per cubic inch was considered high performance efficiency. That’s no longer the case with modern cylinder heads, intake manifolds, and electronic fuel injection.
The G3 Hemi is a great example as it’s shown time and again that it can make massive power numbers with a relatively small displacement. Hughes Engines put their own 392 stroker kit to the test to prove the modern mauler’s mettle and it did not disappoint:
This GEN 3 Hemi was built by our shop F.I. expert, Ben Hoitink, for his ‘75 Duster street machine. The engine is built to have a wide flat torque curve for easy cruising.
The standout feature is the 2 x 4 fuel injection system. The basis is the Edelbrock GEN 3, 2 x 4 carb intake (P/N 7528). The throttle bodies are 2 Holley P/N 112-577. Ben fabricated his own throttle linkage, the throttle bodies work in unison, and the secondaries start opening at about half throttle. Ben installed injector bungs in the manifold.
The Holley wiring system was used without modifications. Holley’s #1 F.I. expert, Rick Anderson, was on hand to make sure we did everything properly as this is the first 2 x 4 injector system—on a HEMI at least for Holley. The engine was a 5.7 with our 392 stroker kit (P/N 5.7 HEMI stroker kit). The heads were the same vintage 5.7 head with full CNC porting, stock valve sizes, and our high flow valve job.
The Hughes SteamRoller cam was an HUG SER2731MHLN with a 111° LSA. As you can see, both the torque and HP curves were very nice: wide and flat, the kind you would like to see in a very hot street “cruiser”.
The vacuum @ idle (750 rpm) was 13”. The torque (that makes it fun on the street) was 450#/ft. or more from 3,200 to 6,100 with a peak of 518 at 4800rpm.
This pussycat is ready to shred the tires at almost any rpm. The horsepower peak was 529 at 5,700 RPM, but the horsepower was over 400 from 4,200 to 7,000 RPM. The horsepower and torque held up well past their peak numbers – not something you see with wedge engines.
Notice how the horsepower only dropped about 21 HP from the peak @ 5,900 to 6,800 – not something you will see in a wedge. Reminds me of the song by the Vanilla Fudge in the 60’s, “You Keep Me Hangin’ On.”
Holley HP EFI
HP ECU #554-113
Throttle bodies 1,000 CFM 4150 #112-577
5.7 heads, fully CNC ported, stock valve size
SER2731MHLN-111° SteamRoller Cam
5.7 HEMI Stroker kit
Edelbrock 2×4 Intake 7528