Instead of squeezing 400 hp from 2.6 liters? The big Yamahas I think are twice that displacement. That's barely bigger than the old 2.4/2.5 200 hp 2-strokes.

Weight?

It seems like weight could still be kept down since most components are aluminum.

better yet why are they still using the old iron duke 3 liter 4 cylinder that is from the late 50s! there are some wicked 4 bangers out there today i keep telling my boy if something happens to his vw passat with a 2.5 5 cylinder i want to put it in a boat, that engine is ultra smooth sounds wicked and rips i think merc is hurting the entry level boats by not marinizing a few better engines

Not aware they were using the old "iron duke" engine. I've always hated that engine. The OBs are pretty advanced now but low on displacement while they look elsewhere to get 350-400 hp out of a 2.6. Yamaha's V-8 350 is 5.3L. Twice as big and probably doesn't have to work as hard to make 350 hp. I'm sure it's heavier though. What happened to the rule that more cubes is always better? Think of the power Merc could get out of a 5L V-6.

Tooling is expensive

Hondas 3.5 v6 is the only variable valve timing outboard i know of .its a big 60degree sohc unit .real simple real durable .real expensive . But oh the possibilities of something like that in a 8.2 v8 version. Especially pre-cat
could have your radical cam for off idle , and no wake zone reversion proof cam profile at idle
of course there is the cadillac blower motor outboard think its the 7 . 5.3 liter ? Unholy expensive

Guys are still racing those old vega blocks in some street class somewhere .and they like the 3.0 stroker cranks .so get em while you can

Here's the real question why dont they build a 502 using the same build tech as they do in a 3.0.

The 7's are based off the 6.2 ls motor out of the CTS-V. They are expensive but they are are also 227hp above the competition it seems.
http://www.boatingmag.com/worlds-lar...boat-show-2015