One of the more common concerns with first time FGF owners is when they notice the engine is not centered in the engine compartment. I was one of those at one point. Here is a pic that shows how far it is offset to the passenger side
Your comment reminded me of an "issue" I ran into with the cooling fan. I believe the stock fan in my '68 Firebird 400ci is supposed to be a 19.5" fan. A previous owner installed an 18" fan w/o a fan clutch (probably to improve cooling...which I also have been chasing). I decided to put a 19.5" fan back in to see if it improved cooling but noted it will not fit in the shroud w/o rubbing. The shroud opening is big enough, but for some reason the fan is not centered in the shroud....and I wondered if someone had installed the engine off center. I was able to move the radiator and shroud over about 1/2, but that still did not provide enough space. I have been trying to figure out what I am missing.
The previous owner may have inadvertently installed a Camaro shroud in it. Many sellers on e-bay and such wrongly list Camaro parts as fitting the firebirds. Look in the Ames performance engineering online catalog to see if it matches what you have.