A 1995 Ford Mustang GT came from the factory with ( 5W-30 )
A 1995 Ford Mustang with the 5.0L engine requires 4.0 quarts of oil.
On a 3.8L 95 mustang the oil filter mounts to the oil pump.
5 Quarts
You go find one and put it in.
5W-20 ( according to the 2001 Ford Mustang Owner Guide )
10w30
5W-20 ( according to the 2004 Ford Mustang Owner Guide )
No, it will not. The clearance tolerances are different.
My ( 1991 ) Ford Mustang 5.0 LX came from the factory with ( 5W-30 )
5 w 20 ( according to the owners manual )
5 qt 5W-30