ORANGE COUNTY

Now rid of its money-losing hospitals and its former name--Greatwest Hospitals Inc.--, HealthCare USA Inc. Tuesday announced the formal signing of its $60-million purchase of Independence Health Plan Inc., of Southfield, Mich. The move makes HealthCare USA the eighth largest health maintenance organization, or HMO, in the nation.

Independence, which becomes a wholly owned subsidiary of Santa Ana-based HealthCare USA, has 100,000 members enrolled in the health maintenance organizations it operates throughout the Midwest. Health Care USA had about 70,000 members.

Independence stock holders will be paid $26 per share of IHP.

Westworld Community Healthcare Inc. of Lake Forest, the fast-growing operator of rural hospitals, has declared a 2-for-1 stock split. Shareholders as of May 20 will be eligible for the new shares which will be distributed June 10.

Northrop Corp.’s electro-mechanical division in Anaheim has received an $8-million contract from the Grumman Corp. to design and build an infrared video automatic tracking system for a Navy’s attack aircraft. The first units are scheduled for delivery in October, 1986.