Best way to do it is either a flatbed or a trailer
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.
No. Not according to owners manual
I calc'ed my '91 V8 Formula Firebird to be about 18 mpg.
tow it
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.
700r4
on the transmission tailshaft housing
it should be on the door lock motor on some early '91 models
Disconnect wires at antenna
yes it is fuel injected.
There are no adjustments on the rear wheels, so no.
91-93 octane premium