I feel its possible and "tuning" vvel is not nessesary, general timing and AFR should be fine. don't forget higher compression pistions. As for fuel, IDK if it will be possible on 93 octane but as for the theory of making approximatly 500whp, I would'nt look past it.
GTM Performance Engineering 1000HP MAF CALIBRATIONN -ANOTHER MILE STONE
^^^vvel not tuned/broken....whatever you want to call it
pulleys, flywheel, 4.5 stroker kit, ported heads, oversized valves, stronger head studs the list goes on I think it could happen.
3.7= .62L per cylinder
4.5= .75L per cylinder
the 300zx TT made 300 HP (N/A 220HP)
nissan made the 370z N/A 332HP
So theoretically .7L increase made the new Z 112HP, so a .8 increase should net a total of approximatly 440HP from the 4.5 stroker kit alone. higher compression pistons, ported heads, flywheel, pullies, oversized valves, larger intake cams........etc etc etc..... COULD be possible chii be ready for a headache bud.