I know of TWO that are currently running fine after 200 hrs of having Whipple on top. These guys have EVERY gauge possible and are watching everthing carefully.
You don't strike me as having been around performance motors much, so I would suggest you steer clear of superchargers. While these motors aren't terrible, they just aren't good candidates for super/turbo charging - unless specifically (re)built for it.
The 496HO is a great engine the way it is. they are not designed to do any modifications to it, altho you can. For the money you will spend on trying to get a few more MPH its not worth the $. A super charger is a for sure gernade. be careful on what you do.
The 496 HO engine from Mercruiser is only built for the serial 425 HP.
When you go to the 500HP range the internal rotating assembly is not strong enough....
My friend has an Paul Pfaff 496 with 650HP on the dyno testet.
Pistion to JE Forged custom made pistons
Rods to forged custom Rods 6.700
Heads to Raylar heads with new valves and stronger springs
Head gasket to cometic
CMI E Top Headers
Aeromotiv fuel pump
Please save your money and buy a 525EFI or a 600SCI
Forged internals Aluminum heads and whippe the 496