What parts??? Body, engine, suspension???
It is listed in the 1991 Pontiac Firebird Operations Manual
A wiring diagram, for a 1991 Pontiac Firebird, can be obtained from most General Motors dealerships. The wiring diagram can also be found at most auto-parts stores.
I calc'ed my '91 V8 Formula Firebird to be about 18 mpg.
i know the backs are 6x9
A firebird can't "have" third gen. It either is or is not a third generation firebird, and Yes, a 1991 is a third generation.
underneath the drivers door
If they are both Chevy V8 cars it will bolt up.
the main vin plate should be mounted on the dash where you can see through the windshield. it should also be on a sticker in the door jam on the drivers side. and on my 1991 firebird it has the vin printed on all the stock windows.
I use 10W-30
I know mine is on the drivers side there is a door in the kick panel
I have a 1990 Pontiac firebird, and the gap on that, I believe is .035. If you still have the sticker under your hood with the engine size, it says it right on there.
Roughly 4.5 quarts with a filter change.