According to the 1998 Ford Mustang Owner Guide :
With engine oil filter change :
The 3.8L V6 engine takes ( 4.7 litres / 5.0 U.S. quarts of 5W-30 )
Start with 4.5 qts. Top off until full and make note of the amount.
SeaScope - 1998 Northern Exposure 1-38 was released on: USA: 1998
The Screen Savers - 1998 2-38 was released on: USA: 18 November 1998
Once you get through all of the available missions and content, there is no longer any aircrat too unlock, you can get a mustang, but not a P-38.
The P-38 was the Lightning, not the Mustang. There were at least 14 fighter versions plus two photo-recce and a night fighter.
I believe that is 35 to 38 point dwell for a 1966 Ford Mustang 200 straight 6 cylinder
Hercules - 1998 Hercules and the Big Sink 1-38 was released on: USA: 11 December 1998
Pocket Dragon Adventures - 1998 Mission Indigestible 1-38 was released on: USA: 1998
maybe
Call for Help - 1998 1-38 was released on: USA: 25 October 2004
35 to 38 dwell at idle RPM for your 200 cubic inch straight 6 cylinder in a 1965 Ford Mustang
E Mysteries and Scandals - 1998 Rita Hayworth 1-38 was released on: USA: 30 November 1998