An extremely good and safe Tune with a blower cams and heads your really going to be pushing those stock rods/ pistons , if I were you I would ditch the heads for now and do forged mmr or ne preferred bottom end and about 14lbs of boost along with a nice set of blower cams you should be over 500 hp with supporting mods and fuel
Totally stock motor and normal ProCharger pulley will get you around 350 rwhp. Drop to a smaller pulley and you can make more. Drop too small and you will scatter parts of your motor all over the highway.
Stated horsepower is a tricky thing. Dyno operators use national standards to tell us the horsepower of our cars. Since we live all over the place they have created standard adjustments for the dynos. That way someone at 6,000 feet can compare to someone at sea level. Almost all dynos use one of two standards: SAE or STD. Typically STD will show more horsepower than SAE. But these corrected numbers are not what blows up motors. It is actual stress... the raw numbers... that blows up motors. If you live at high altitudes then you can run SAE or STD higher horsepower safely than those at lower altitudes because you uncorrected numbers are a lot lower.