Best aftermarket addition to twin 454's
 

Have 97 29 outlaw. All stock except for k&N arrestors. Looking for a lil bit more out of it. While still keeping the boat reliable and not having to worry about break downs. What should I be looking at headers, different props, ?? Any sites anyone would recommend. THanks fellas

Probably depends on what horsepower your 454 is now.
I have a 454/330 in my jetboat. Changed the heads to rectangular port units. -this made a big difference.
Changed the cam. - nothing radical but much much better than stock. Combined with the heads, this made the biggest difference.
Also added a better intake, and later added lightning headers.

Just as reliable as it ever was. Made those changes about 6-8 years ago. sounds better, looks better, and performance gain was significant. Still a pretty mild motor, but is night and day compared to what it used to be.