I have a solid backround when it comes to engine building but not so much on current options as far as marine use goes. Maybe someone here would be kind enough to offer some sound advice on my build.
Let me start with what my goals and intended use are...
Family bowrider used for skiing and tow-able toys but at the same time be able to take a nonstop 75 mile trip at 40-45 mph cruise.
With that said I think that through the prop exhaust and modest fuel efficiency are a must.
The boat is a 1995 Donzi 212 Medallion bowrider. Currently 100% stock original w 454 330hp w/ Bravo 1. Boat weighs aprox 3500 lbs and has 8.5' beam. This is not a high speed narrow hull. It has seen 57mph gps in this stock configuration.
The 330hp 454 is now junk. It knocks and has seen over 30 years of salt water cooling. Its time to repower.

I acquired a very nice condition low hour 385 magnum 454 and will be using this Gen6 4 bolt main factory roller cam block as the starting point for the 489/496 build.
I also got a very nice deal on a Bravo 3 drive with 2.0 ratio and 29p props and condition is like brand new (btw I am content with top speeds in the high 50's).
Im thinking the Bravo 3 will be extremely beneficial for skiing/towing as apposed to the Bravo 1 which will be kept aside as a speed option for other times if desired.


My questions are with this stroker build what should I do for camshaft profile (was told ZZ502 is good choice) , crankshaft (brand? cast or forged?) and compression ratio (piston choice?)
Parts I have.
Gil/Mercruiser aluminum 496 HO manifolds to be run down through transom and out the prop
Freshly built RHS 118cc Rectangle port heads with stock valve springs and inconel exhaust valves
Aluminum dual plane snowflake highrise intake with brass inserts (type used for 380hp magnum with carb)
Edelbrock 750cfm spreadbore marine carb (big enough)
Factory roller lifters and stock pushrods
Factory Thunderbolt ignition
Also I will be buying roller rockers too. Was thinking Comp Cams 1620 rockers

I am open to all suggestions. My concerns are which stroker kit to buy. So many options.
If I don't need a forged crank then great. And can I go with 10:1 cr with iron heads? Maybe 9.5:1?
Which hyd roller cam would be best without having risk of water reversion?
Can I use the (mint condition) factory roller lifters with more aggressive camshaft profile?
I need an electric fuel pump (no provision on gen 6 block). Which one is best for my application?
Which head gaskets should I use (saltwater cooled)
Sorry to post so much info and questions but figure the most accurate answers will come once all specifics are covered.

Fuel economy in a boat. Seriously! First off with iron heads single engine v bottom 3,500 pds I would try keep it under 9.5:1 especially if you plan on running 89 or under octane. The ZZ502.cam is on a 110 lobe separation I'm pretty sure and will without a doubt revert. Considering your going through hub you should probably look for 114 LSA. There are a lot of good proven marine cams. The crane 168791 on a 114 would be a good choice for your cubic inch while staying somewhat conservative yesterday make decent power. If your going with more CI and better heads you might as well give it more cam. The 1620 rockers are good choice.

I gues it depends on what your looking for hp wise.

Head gaskets I'm not real savvy for salt water use however cpperformance or Teague all offer marine head gaskets and brand is a matter of preference.

Im thinking 425-450hp is a solid goal. As for fuel economy I don't mean good fuel economy lol. I mean not going overboard and wasting fuel at cruise just to have 25 additional hp. In other words proper carb and cam choices.
Im pretty sure the 731 cam your suggesting is obsolete. In case this helps my stainless (wet) risers are about 18" long and pointing downwards. Yes the zz502 cam is 110 LSA

Jegs has also and can ship sooner.
https://www.summitracing.com/parts/crn-168791

Why not freshen up the 385, maybe bump compression half a point, some iron eagle 308 heads and call it good? If you'e ok with mid to high 50's and it ran 57 with a tired 330 seems easy to me

Top speed expectations are not high because of the hull design. Im after a much improved holeshot. Torque of a 496 is gunna help with that. As for the heads im not familiar with the Iron Eagle 308 heads but My RHS heads are very nice.and I already had them built.
Any advice on crankshaft? Is it ok to use a cast crank?

If you significantly increase torque enough to make a big difference and use it, you are going to break the bravo 3. No I wouldn't use a cast crank.

So you want to build a motor with more horsepower, more torque, longer stroke and use a weaker crankshaft??

So Phragle and Unlimited jd... In your "professional" opinion I must spend $600 more for the forged crank? Why would the aftermarket be making cast stroker cranks if 450hp is too much for them?
What I want is to build the best possible engine without spending extra money I don't need to spend (this is an old POS boat). If I knew everything I wouldn't have asked questions. Looking forward to responses that help rather than criticism. The only info I got so far is what "not to do" and without explanation (except for getrdunn's cam advice).
Im a Porsche mechanic not a marine mechanic. Im just asking for qualified help. Did I come to the wrong place? I get that its winter and you guys would rather be out smashing waves, but show a new member some love.

Drag racing, street cars, hot rods etc. mercury uses a forged crank on everything above 365hp. Constant load for extended use, and low end torque sounds like everything you wouldn't want to use a cast crank for.