gcc change from 4.0 to 3.4

[Marco Calviani]

Hi list,
   i'm asking if there is some way to change the default compiler and
related variables in a consistent way to another version. In
particular i would like to change it, due to some incompatibilies,
from 4.0 to 3.4. I've tried the "brutal" way changing the symlink of
gcc to gcc-4.0 to gcc-3.4, but it was not so succesful.

Thanks in advance,
MC