Refinement continues on the Quad Cam 4-valve engine platform at Mercury Racing, the company said.
Mercury has been doing dynamometer and in-boat endurance testing since the engine was introduced at the 2010 Miami International Boat Show. The development team also has been refining calibration of the engine and Digital Zero Effort controls - both in Mercury Racing's test boats and in the 46 Cigarette.
Development remains on schedule and production of the 1,350-hp QC4v will begin this month, as announced in February.
Shipments of the 1,350-hp engines, M8 drives and Digital Zero Effort controls will begin in August. The first pair will go into the AMG Cigarette, replacing the production validation test hardware now installed.
The company said production of the engine and M8 drive is sold out into March 2011.
Mercury Racing is a division of Mercury Marine, which is based in Fond du Lac, Wis.