As such, it featured the M186's innovative aluminium head, which had a 30-degree diagonal base that allowed for larger intake and exhaust valves than a standard horizontal joint with the engine block. To improve performance, the M198 replaced the W194's triple two-barrel Solex carburetors with a Bosch mechanical direct fuel injection system. Derived from the DB 601 V12 used on the Messerschmitt Bf 109E fighter of World War II, it boosted power almost 25% over the Gran Prix cars, raising output from SAE gross to SAE gross at 6100 rpm ( DIN at 5800 rpm), over double that of the original Type 300 saloon's SAE gross. Compression was set at 8.55:1.