Did you take the pistons and have them do the bore for the pistons you are using? That's important.  Any shop will
bore the block to the pistons that are being use.  The blueing I don't see a problem with.  I have to ask reading that you are building a 455 is that does the shop you are having do you work know the 455 motor?


Sent from my iPhone using SoCal Jet Boats

  ok GT looks like I have some info to look up I've done car motors but never a boat motor, why the difference?

Think about it this way.

The marine engine is under a huge load as compared to a car motor. That creates a ton of cylinder heat and oil temperature.  At the same time, they are running with very cold cooling water and you want cost temperatures mainly because of the untreated water.

The pistons will expand at or greater than they normally would, whereas the block would stay cold and not gain the thermal growth.

So the piston could technically hot seize or the rings could bite and pop the top right off  of the piston.

Depending on piston material and type, the clearance needs to be wider.

Good that all makes sense.

GT

I have to say it out loud.

If you want a thermostat kit, I say go for it. But don't think that they actually "control" the engine temp. They control the outlet temp. Which is different.

A proper thermostat kit involves a a block mounted automotive style water pump. Are you at all familiar with how the water flows through a block?  If you did, you would understand where I am going.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app

Neither am I.

That being said. Restricting the water leaving the block until it gets to a certain temperature is fine, as long as the water within the block and heads is moving and homongenous.

With the regular thermostat kit found virtually anywhere now,  the water simply is slowed, not circulated.

The water flows from the water pump holes through the block, to the rear of the heads, from the rear of the heads to the front of the intake manifold. They're are some small holes in the gasket along the way, but for the most part, that is the travel of flow.

In an open system, the easiest way to totally control the temperature is a water pump style austen like what is found on an I/O.

Don't get me wrong, the stat kits help and I have used them with some success,  but be warned, they are not fool proof.

With the stat kit, the front two cylinders will run extreme cold with the hottest combustion chamber temps. Not a real good recipe for longevity.

With a true open, limited flow system, everything is pretty cool. Also making everything consistent temperature wise from one cylinder to the next. As long as the engine is built right, it will run forever.

GT

Sent from my SCH-I545 using SoCal Jet Boats mobile app