They are stock vortec heads. Not sure which valves are in them.

reportedly pocket porting on the exhaust is worth 20-25 hp and you can do that yourself.

Ive heard that but too nervous to attempt it on my own. Have never tried that before.

On a cast iron head nothing happens fast , trust me you'll be most of a day with the grinder. You're not really reshaping just cleaning up some material the accountants told the engineers to not worry about. Go to a machine shop and get a cracked cylinder head and give it a shot.

for a cam,,you need the tried and true........wait for it


3/4 race cam,,it fixes everything.

and a tunnel ram w/ 2 dominators

Sorry to the OP, many of us are retarded and get worse during the winter.

Here is one if several threads on subject:
2004 350 MAG MPI cam, ecm upgrade?

You will need minimum better valves springs and pcm programming.

If your boat is heavy and slow, this may not be worth it. If boat is already quick , you will see some gains.