Six Pack System Test - Six Pack Dyno Charge

Oh, the fabled Six Pack and the memories it brings. For me it harkens back to high school in the late '70s, when the local dealership mechanic flipped a complete aluminum-intake 440 Six Pack setup my way for a mere 75 bucks. Those fat six barrels running the length of the intake were pure visual candy-so much more than the plain-jane AVS four-barrel and iron intake they were replacing on my prized R/T. When they worked, it was sweet music, a rush of adrenaline that came with the surge of air pulled through those six gaping holes and into that mighty 440. It was addictive, and I came away bitten, another Six Pack junkie for life.

It lasted less than a month before fouled needles and seats had them overflowing with fuel, and the cheap parts-kit replacement cork gaskets of the day made them worthless for metering fuel. Numerous rebuilds and mods eventually took their toll, until stripped-out float bowls dealt the final deathblow. A boneyard yielded a complete replacement system-an iron intake setup marked "70 Charger" in that familiar wrecking-yard paint-pen yellow. Those carbs, too, were a constant effort to maintain, until, for the sake of reliability, the Six Pack was sacked in favor of a Holley 3310 750 on an old Edelbrock Torker intake. The surge of power, as I remember it, was never the same. While those old Six Pack carbs were problematic, the magic of how it ran when it was "on" remains with me to this day.

Were Six Packs really as good as we remember them? It's clear now that my carb's reliability problems were because of inexperienced hands and bogus cheapo parts. The memory of big power remains, but some of our non-Mopar buddies and coworkers scoff. When we jawboned around the office about an upcoming Six Pack tuning test, the cynics were out in force. We heard it all.

"Looks cool, but has no place on a performance engine today."

"Might have been better than stock 30 years ago, but no match for a modern induction."

"You're going to run that thing? Good luck."

It could just have been nostalgia, but we figured the 440 Six Pack induction would prove its worth. We were intent on running the system on the dyno and letting the numbers tell the story.

Our test Six Pack system is a far cry from the dusty and dried-out junkyard parts I remember from decades ago. That aluminum intake scored in the '70s had been brutalized with oversized drilled-out mounting holes to fit a set of milled heads, and barely held the carb fasteners with its war-worn threads. Twenty-plus years later I've finally assembled a Six Pack worthy of the legend. The test intake is a new Edelbrock piece, cast true to the original aluminum '69 version. Rather than ragged and rebuilt junkyard carbs, on hand is a fresh set of re-released Holley resto carbs, a #4670 center unit with a brace of #4672 outboards. Assembled from all-new components, the Six Pack induction is as much a work of art as a fuel system.

Our intention was to explore the performance potential of the Six Pack on a modern street/strip performance-built 440. We had a fresh Edelbrock-headed 440 at Westech's dyno shop, which had been built as part of Car Craft magazine's series on big-block performance engines. The 440 had been run in numerous dyno tests in various configurations, and produced righteous output. Build specs on the engine-a balanced and blueprinted stock bottom-end featuring .030 over TRW 2355 Six Pack pistons dialed in to yield 10.2:1 compression; a Comp XE285HL .904-inch tappet ramp hydraulic cam; 1.6:1 Harland Sharpe rockers; the aforementioned Edelbrock heads; and Hooker 2-inch Super Comp headers. In previous dyno work, the Edelbrock Performer RPM intake proved to be the best single four-barrel intake tested by a significant margin. It represents the state of the art in modern four-barrel dual-plane intake manifold design. We used the RPM intake as the baseline, to see how the Six Pack compares.