you can get a ton more power by doing heads and cam on an ls7 than any stock block engine that came with the GTO. you don't need to do boost.
LS7 Z06's run 9's with heads and cam and get 600+ whp.
if it is, keep it. that thing will be a monster if you mod it.
the only thing i would worry about is the valve seat eccentricity. but, if you do the heads, you should have that covered anyhow.