I think your best bet for gcc is to get the tarball directly from the
GNU project and install in /usr/local. I have done this before and it
works well enough. IIRC, the instructions for building from source are
clear enough.
The old versions of some compilers and standard libraries are available in Fedora as packages with compat in the name, eg compat-gcc-34 and compat-gcc-296. Like the others have answered, however, you'll probably have an easier time either building an F8 VM or setting up a dual boot. Old versions of Fedora plus (old) updates can be downloaded from the archives.
And finally configure, build and install it. It took around 20minutes on my machine. I installed this gcc version not in my native PATH, as I didn't want any collisions, I choose ../build as a suitable destination. In this case you have to remember to modify your PATH and LD_LIBRARY_PATH environment variables. So the app (e.g. nvcc) in question is looking in the right path when calling gcc.
I can also consider adding the --program-suffix=4.3.4 to add the given suffix to all binaries, this makes sense when you install this build into %{_bindir} and %{_libdir}.
Finally you can launch nvcc or whatever application is requiring gcc-4.3.4.