Yes it will fit, They are exactly the same body style
No
No, the engine will not fit. The engine of 1999 is designed to be compatible with the car's other parts, but if you were to put a 1998 engine into a 1999 car it would not work properly.
Can a v.8 5.7l 350 engine fit into a 1994 Pontiac firebird?
yes it will work.
Some parts will fit, depends specifically on what parts you're referring to
Yes, as any small block engine will fit.
Yes
Most likely, if the 1998 is a 250 also
yes
Any size SBC engine will fit and is compatible with a 91 Firebird. A 350 engine is the most common that is used for installing in a 91 Firebird.
Yes it will. Any rear end from 1993 to 2002 will fit. All the parts are interchangable from 1993 to 2002. In 1998 the front end was changed a little but the rear end stayed the same.
yes all 4th generation(1993-2002) firebird parts should fit in other 4th gen firebirds