What am I looking at cost wise to produce 525HP.....right now it makes 390HP at the prop..........it has the switchable exhaust and has a closed cooling system...I would like to keep the closed cooling, but the exhaust can go (I like it loud anyway)

about 5 to 6k

Start looking for a Blower , and be done with it

A set of nicely ported ovals, a 226/234 112 .600 hydro roller, 800 Holley and about 9.6:1 should get you there no problem

Get good exhaust since you're gonna replace.

DAVE

just copy a hp 500 but put a crane 721 and rollers rockers and a dart intake, 750 dbl pumper and get the heads ported and polished that should do it with good exhaust

zz502 aluminum heads,intake and a custom grind cam with some roller rockers/lifters,830-850 cfm carb and good exhaust will do the job.