Whats a safe limits to take this engine to?

I bought a used 20005 stang convertable in very nice condition with recently rebuilt engine.
Procharger high-output kit with upgraded P1X supercharger Deka 80 lb injectors Ford racing intake Bbk throttle body 1-piece ford racing drive shaft Manley forged piston -6cc Manley rings Forged rods Comp cam beehive springs and retainers Comp cam blower cam 222/239 Melling high flow oil pump Return Style fuel system 400 lph fuel pump Long tube headers Ferrea intake and exhaust valves Mccleod prostreet clutch Vmp Maf , large intercooler.

Engine bored over to 0.20 is purring like a babe . Puts out 521rwh and 478 tq via rebuild trany. Question is what would be a safe limits to turn a boost up with a good tune. I also do not mind running some water meth in it.

All 4.6 2v experts - please chime in

I just saw my typo. I thought big blue oval guys would be a bit swetter than Corvett biggots crowd but live and learn )))))))))))))))))

Any advices though