To those interested in power output, nothing has the attraction of a supercharger. Forcing atmosphere into an engine makes it take a charge out of proportion to its displacement, and, with that, produce power out of proportion to its size. There are many types of supercharger systems used in automotive applications, from turbos to positive displacement Roots-style blowers, to beltdriven centrifugal units. Each has their pros and cons, with turbos getting a nod for efficiency, but often presenting an installation nightmare. Traditional Roots blowers are capable of effective low-rpm boost, though they are too ostentatious for some and are no lightweights. Beltdriven centrifugal blowers have become popular for several reasons: The systems are relatively easy to install, offer increasing boost with rpm, and the big bottom line is they make serious power.
The leader in Mopar musclecar centrifugal blowers is a company called The Supercharger Store. We looked longingly at some of their well-designed products at various Mopar events for several years now, and decided to finally take the plunge into the realm of boosted power. The Supercharger Store systems are based on the ATI Procharger line of blower units, superchargers that are well proven in drag racing and street applications. Most of the ATI blowers are fully self-contained, meaning they carry their own internal lubrication supply, eliminating the need for plumbing pressure and return lines between the blower and the engine. The Supercharger Store has many variations of blower systems and components specifically for Mopar applications, so we had many options to consider when formulating a plan for a blown big-block Mopar.
Popular kits are based on blowers of various capacities, depending upon the boost level and power objectives. Initially we were going to go with a basic street kit, built around the 1,400-cfm D1SC Procharger. Later, we reconsidered the project and settled upon the much larger capacity F1-R, a hotter version of the 1,525-cfm F1, rated for 2,000 cfm. This unit would be enough to easily produce high boost in a 440ci engine, and yet have the capacity to handle the greater needs of a high-output stroker combination if we later choose to go that route. Boost pressure is dependant upon sizing as well as rpm, and the rpm can be adjusted within the unit's operating range by the selection of blower pulleys. Our intention was to use the F1-R on a typical bracket race/street style 440 and spin it for high boost. Our engine makes peak power naturally aspirated at roughly 6,000 rpm, with a redline of 6,700 rpm, so those points are established. The drive pulley ratio can be determined by the operating rpm range, the displacement, and the targeted boost. The Supercharger Store has the data to match sizing for the required goals.
 Our supercharger plans centered...  Our supercharger plans centered on a very typical 440 combination. It's basically a 0.030-inch overbored 440 block with a factory steel crank, forged pistons, and Edelbrock heads, with a compression ratio of 10.3:1. This engine had produced as much as 550 hp in normally aspirated form, with a Comp Cams 239/247-degrees at.050-inch lift, 0.573/0.597-inch lift, solid lifter cam. |
 Since we were making the move...  Since we were making the move to boosted power and intended to keep compatibility with pump gas with a fairly high boost pressure, the engine's 10.3:1 compression ratio was deemed too high. Rather than the expensive route of changing pistons, we decided to try a set of extra-thick, rubber-coated copper head spacer/gaskets from Flatout gaskets. We have used the Flatout copper gaskets in the past and found them to be of very good quality. They are available in a variety of thickness', with these spacer units measuring 0.125-inch thick. The spacers can be run in conjunction with conventional head gaskets. With this combination, we would reduce the compression ratio by over two points to 8.1:1. |
 Because of the thickness of...  Because of the thickness of the gasket stack with the spacers, the cylinder head dowels in the block need to be reset or replaced with longer ones to provide an adequate register into the head. |