I have never heard of any engine builder willing to give a customer cash back on a mistake. The engine builder will want you to let them fix the issues at best.

Just a casual observer, but from comments I've read and little bit off other thread.......give you my .02.

Politely presenting your evidence and allowing him a chance to comment is worth a shot because you got nothing to lose at this point. I would approach it as "I had read that marine applications require different clearances and so you went to the manufacturer got the specs and this is what you found vs what you got. Is there something I left out that may of steered you in the wrong direction.....". If he offers to fix say great, but ask what will be different this time? Look at him dead in the eyes and read him, if he is looking to the right and up he is lying and can't be trusted take your stuff somewhere else and let god do the rest.

Also, in this sport, you need a second boat, give a care if it's a 17-20ft bay boat or craig cat or whatever. This sport will chew up a season quicker than a pack of chewing gum.

I am going to play the part of your engine builder.
Me; So you Dyno'd the engines, they ran fine, had good oil pressure and made the power you were looking for?
You; that is correct
Me; So what is the problem?
You; I read on the internet that I need more clearance on the pistons and valve guides
Me; No problem, I can do that for $3K each
You; I want you to do it for free or give me $6K
Me; (laughing) GET OUT OF MY SHOP

At least that is how I see it going down. Now if a piston had seized or popped off the top ring land while warming up on the dyno that would be a different set of circumstances that he might stand behind.

The heads I don't see him doing anything with as you presented them to him as ready to run....now being a competent builder he should have suggested otherwise but didn't so I think you're out of luck on those.

The ring gap, bearing clearance, and piston clearance are things that he chose not to at least follow the manufacturer's instructions on. My opinion you do have a case there however I don't see him redoing it for free..and even if he did, would you trust that he did it correctly to what you asked of him or did he just print you a new piece of paper with the numbers on it that you wanted to see? Either way to me I would probably go elsewhere but I have been burned a couple times so it's really a crapshoot I'd say unfortunately

Thanks snapmorgan for your comments. I'm pretty sure you know that my complaint is not that I met my power requirements like you appear to indicate is the problem. Maybe it was unclear, but these engines are exactly what I was looking for in hp and torque.
I did learn all sorts of info from this site pertaining to clearance's, valve springs and guides, etc. and will be meeting my builder tonight to go over everything.
The piston to wall clearance is on the sheet provided by the piston manufacturer for a marine installation. My builder spec'd and supplied these pistons. My thought is that the piston manufacturer has some idea of how the parts they produce will react in different circumstances. My builder didn't follow that suggestion (in fact they are so tight that the installed clearance is not even listed on their sheet) and I'd like to know why especially if it may strand me in the middle of the lake. Same for the ring end gaps.
Snapmorgan, I don't know if you're an engine builder or not but I will assume that you are. When you install pistons, do you just install them to your spec's and if it fails out on the water the answer is "GET OUT OF MY SHOP?" Are you offended with any customer that approaches you and starts the conversation out with: "The guys on the internet said..."? I know my builder is and I think he should be.
Also my understanding is that although they did survive a few "momentary pulls" on the dyno doesn't mean that they will stay together running at WOT across the water for an extended period of time.
I won't ask for something in writing but I will ask for "assurance" that the builds will survive under normal conditions. I absolutely don't want to have any problems and for an example of mistreatment, I wouldn't start them Saturday morning and 15 seconds later go WOT down the river.
Now that I have already "accused him" of this error, I'm hoping that if I actually bring something up to him that he does see as problematic, he would be man enough to own it now and help me to get it properly sorted out before installation. I'm pretty sure especially after snapmorgans input that regardless of the failure (if one even happens) it will be 100% my fault and 100% my problem.
I do appreciate all of the comments whether helpful or not.
Thanks again.

I think snapmorgan is just saying that’s how he sees the conversation going, not that he would react that way.
Nothing about these builds is correct. It’s time to step back, take them to someone that knows what they are doing and have them go through everything and fix them.
Will your pistons and cranks live at that power level? Probably, but I sure like to build a marine engine a lot more towards overkill.
Mercury and their penny counters built 365 hp engines with forged rotating assemblies. If they thought cast would be just fine they would have used it.

More accurately, Mercury and their penny counters bought engines from GM that happened to have forged rotating assemblies in them. Need look no further than the 496 to show that Merc wasn't dead set on forged for black motor purposes.

Maybe Merc had no choice with the 496 ? :wink

Well, they have the resources to have engineered their own forged parts if they wanted to. There just wasn't a good reason (i.e. profit) to do it at stock power levels I guess.

If they did a blue motor based 496, they would have.

All my opinion of course.