Once at the Supercharger store, the engine was fitted with a Holley 750 cfm carburetor and off the shelf tti step headers and the ProCharger D-1SC supercharger and water injection kit was installed but left inoperable for the moment. Purchasing ten gallons of the cheapest 91 octane fuel they could find on the way to the dyno, the engine was then taken to Larry's Engine and Marine in Tucson, Arizona, for its initial testing. While Dave Hughes predicted the small-block would make around 360 horsepower normally aspirated, the little 318 actually did better, making a best pull of 370 horsepower at 5,800 rpm, with 349 lb/ft of torque at 4,900 rpm, at only 30 degrees of ignition timing. With the baseline established, Bob Woods and his team from the Supercharger Store quickly installed the belt on the ProCharger and filled the water injection system reservoir. Since the additional air flow would require more fuel, a special 750-cfm Holley "blow through" carburetor was installed as well.

After firing up the engine and verifying it was running properly, the ignition timing was backed down to 28 degrees total advance for the first dyno pull with the supercharger pumping. Unfortunately, the 318 wouldn't idle at that low setting due to the initial timing being at zero degrees, so the factory Chrysler distributor was removed and modified to increase initial timing. With this modification performed, the now supercharged 318 idled cleanly at 900 rpm with 12 inches of manifold vacuum, and was deemed ready for dyno pulls.

With Bill Rohlinger of Goal 45 Motorsports assisting Larry's Engine and Marine with tuning and dyno testing, the 323-inch 318 netted 630 horsepower at 6,000 rpm on its initial pull. With some additional tuning, and by adding timing two degrees at a time until reaching 34 degrees total advance, the engine responded nicely and made additional power with each subsequent dyno pull. On its best pull, with 14.59 psi of boost and 34 degrees of timing, the 318 produced 662.7 horsepower at 6,000 rpm, and 587.5 lb/ft of torque at 5,800 rpm. To ensure durability, the engine was pulled three times in this state of tune, producing nearly identical numbers on each pull. Though just shy of their peak torque goal of 600 lb/ft, the engine hadn't yet peaked during this test session and likely would have made this number with simply another bump in ignition timing.

Overall, we'd say Hughes Engines and The Supercharger Store definitely met their goal of building a small-block that would equal or better the power numbers of a normally aspirated, stroker big-block on pump gas. Had the engine been based on the more popular (but less available) 360 small-block Mopar, the torque would have certainly gone up considerably, easily topping the 600 lb/ft mark. With 305 lb/ft of torque at a low 2,400 rpm, this engine should launch a car of moderate weight reasonably well, even without the benefit of a loose converter or high rear gear ratio, and with nearly 600 lb/ft of peak torque and over 660 horsepower on tap, this little 318 would make any Mopar a fun ride, proving that there is, in fact, a replacement for displacement! Be sure to watch future issues as we plan to install this engine in a '73 Plymouth Scamp for some real-world track and road testing.

Comparing apples to oranges
This month we learned how a mildly modified 318 compares to itself in normally aspirated, and supercharged, form but how does the 318 in this build compare with normally aspirated engines built specifically to make high power on pump gas? Judging by the numbers posted by the most powerful big- and small-block engines in our recent Amsoil/Mopar Muscle Engine Challenges, we'd say this 318 compares very well.

While there is something to be said for making big power without the benefit (or complication) of a "power-adder" like a supercharger, turbo, or nitrous oxide, normally-aspirated engines making big horsepower typically must be revved higher, requiring far bigger camshafts, much looser torque converters, and steeper rear gears to get their power to the pavement. So, with reliable supercharger kits available for nearly every conceivable Mopar these days, more enthusiasts seem to be choosing this option. Which is right for you? Here are some comparison engines with horsepower and torque numbers to help you decide.

3416 Democrat Road
TN  38118
The Supercharger Store
314 W Highway 82
Huachuca City
AZ  85616
Hughes Engines
23334 Wiegand Lane
IL  61571
Tube Technologies, Inc.
1555 Consumer Circle
CA  92880
Accessible Technologies
14801 W. 114th Terrace
KS  66125
Goal 45 Motorsports
Total Seal Inc
22642 North 15th Avenue
AZ  85027
Larry's Engine And Marine
600 West Lester
AZ  85705
Eagle Specialty Products, Inc.
8530 Aaron Lane
MS  38671
Diamond Pistons
23003 Diamond Drive
Clinton Township
MI  48035