Isn't supposed to happen, but 512 lb-ft of torque and 504 hp from a stock 350 short-block and stock Vortec heads is awesome!
The wheeze is that big things come in small packages. That may work for diamonds and dynamite, but it's not supposed to work for blowers.
Don't let the small size of this blower fool you. We made 504 hp on a stock 350 short-block with Vortec heads, a mild hydraulic cam, and a full street exhaust system.
"That blower won't make big power-it's just too small." That was our opinion of Magnuson's new 122ci Magna Charger carbureted supercharger just before we started our dyno test. Jerry Magnuson's company has been building performance versions of the Eaton supercharger for a long time. This blower has made a name for itself making great power in late-model EFI cars like LS1 Corvettes and trucks, but until now, Magnuson had no carbureted version. Plus, the common perception was this blower was just too small to make any real power. After a half-century of giant 6-71 and 8-71 huffers protruding through the hoods of thousands of hot rods and musclecars, it is difficult to accept that a tiny little blower like this could compete. But following the first yank on the dyno handle at Duttweiler Performance, we threw out those old misconceptions and started a new mantra-small is big. Magnuson's new High Helix, 122ci displacement supercharger is about to set the boulevard on fire. With the power our little small-block made, Jerry Magnuson should be buying stock in Firestone, BFG, and Goodyear because this little blower makes enough steam to melt tires at will.
The Magnuson 122 is not much bigger than a loaf of bread. The other important point to make here is the new Magnuson manifold allows this blower to be used with production Vortec heads.
Here's the meat of this story: We bolted a 122ci High Helix Magna Charger carbureted-style supercharger to a painfully mild 350ci, 8.25:1 compression small-block Chevy outfitted with almost-stock iron Vortec heads and a mild Crane supercharger-spec hydraulic flat-tappet camshaft. On pump gas with a good supercharger-style 750-cfm Holley carburetor, this little Mouse made 512 lb-ft of torque and 504 hp, stacking a stunning 140 hp on top of the normally aspirated power numbers at the top end. And the blower achieved this amazing feat with single-digit boost numbers. The results were so stout that at first we didn't believe them. And the best part is this blower is the deal of the decade with a list price of $2,395.
On the EFI versions of the Magna Charger, the air enters the blower from the rear, which, according to Magnuson, is even more efficient than air entering from the top with a carburetor. Magnuson also offers an EFI-based package to be used on the early small-blocks.
We've outlined the parts we used, so you know all the pieces and how brutally simple it would be to duplicate our numbers.
Inside the Magna Charger
The Magnuson supercharger is based on the original Eaton three-lobe supercharger. Most Roots-style superchargers are sized according to displacement, which is the number of cubic inches of air displaced for each revolution the blower makes. For example, the 6-71 GMC blower actually displaces 411 ci of air per revolution. The point of this particular test is that efficiency is more important than size. The Magna Charger supercharger used in our test displaces a mere 122 ci yet makes excellent power. What's new is this smaller blower employs a 60-degree twist to form a helix that creates a more efficient movement of air that reduces the temperature rise. This means the air exiting the blower is cooler than the discharge temperature of a less-efficient blower. Cooler air is denser, and that's where the power comes from.