The new MGB supercharger system uses the same Eaton positive displacement roots-type supercharger found on contemporary OE applications such as Mercedes Benz and Jaguar. In spite of its modern origin, Moss was careful to design the system to look like it was a factory-installed option that complements the classic MG image.

Moss engineers designed an intake manifold that provides equal airflow, pressure and fuel mixture to each cylinder. By optimizing the distribution in the manifold for each cylinder, you can run more boost pressure without the chance of harmful detonation. The Moss supercharger system produces 5-6 PSI of boost at sea level. On our otherwise stock test car, that almost doubled the rear wheel horsepower. Bolted on to a stock engine you may expect a HP increase of 40% at the flywheel. Click Here to view Dyno Sheet details.

The Supercharger kit is very complete and includes a 4-rib serpentine belt drive system, new cast iron water pump, a set of colder NGK BPR7ES sparkplugs and a high-flow K&N air filter. The 1968-74.5 kit also includes a new Lucas high output alternator.

The 1965-67 kit fits 5 main engines with generator.  For these vehicles we also offer an alternator conversion kit which includes a new high output alternator, four rib pulley, all connectors and full instructions for converting the car from positive to negative ground. The alternator has more durable bearings than the generator and will offer greater performance.

The installation can be completed by a competent mechanic or hobbyist with hand tools in about nine hours. Our Frequently Asked Questions listing for more information is available Here.  The complete installation instruction sheet is available by clicking the "More Info" button.

For a complete listing of our MGB Boost gauges click Here

Please note:  These kits are designed to be installed on engines that are in good condition with the original compression ratio and correctly operating distributor and fuel system.  Increased compression due to block or head modification, worn distributor components, or a weak fuel pump can contribute to damaging detonation under load. 

The Big Boost Pulley Upgrade Kit should only be installed on low compression engines or those where head modifications allow a higher boost without detonation. Boost will be increased to 7.5-8.25 PSI.