26sonic

have a 1998 502 efi with the following done : exhaust , k+n air cleaner , ecu reprog., msd ignit, adj. fuel reg. talked to crockett marine and said he can change cam do head work and ecu and give me 490-500 hp . other option is m3 pro chrger with 3.5-5 lbs boost . which system gives most gains and reliability ? also cost of charger and install is about $8k and up grading with cam, head work and ecu is about $2k any opinions ?

mcollinstn

The cost issue should be an indicator.

Most gains? The 25% increase that 4 pounds of boost delivers will net you around 100 horses.
The 80 horses that the other work gives you will not compare to the midrange acceleration you will get from the procharger.

I would add an additional $700 to the procharger plan and drop in a cam at the same time. Now you've picked up 175 horses.

That's just me.