how hard is it to put a chevy 350 into a 85 fiero?

That would likely be quite difficult. Unless you have experience and a professional shop at your disposal, I would forget that idea. The Fiero did come out with a V-6 engine though. So that might be a more do able project for one that asks questions such as these. Best of Luck.

I currently have a SBC (fuel injected 383) in a 1988 Mera (Fiero dealer option) and many SBC engines have been installed in Fieros (both carburated and fuel injected). An adapter plate is required to mate the manual Getrag 282 transmission to the engine but there are kits available for the conversion (see V8Archie for more info). Nelson

Second photo of 383 engine installed in a 88 Fiero. Nelson

Engine prior to installation accidentally posted above. This picture shows the completed engine installation. Nelson