Preliminary first quarter reports put Detroit Diesel Corp. revenues at $536 million and net income at $10.1 million.

Revenues for first quarter 1999 were $592 million; net income was $12.5 million. But gross margin for the quarter is estimated at 24.9%, an increase of 1.4% over last year.
Chairman Roger Penske said at a recent stockholders meeting that shipments of its Series 60 engines were down 14% due to expected lower production of North American Class 8 trucks. The decline was partially offset by stronger service parts and remanufactured product sales as well as increased sales of its Series 2000 and Series 4000 engines.
Final results for first quarter will be released April 27.