high hours 5.7 prostar

[GregHind]

Saw a really high hour 2014-2020 5.7 prostar and wondered what the options are for motor refresh. New 5.7's are not available so what can be done? With the high levels of integration, can you still swap the motor out for a different type i.e can you buy a new 6.0 or 6.2 and drop it in? Is there a way of getting an aftermarket 5.7 long block and putting that in? What can you do? 

[dvskier]

I think a lot of people get overly concerned with hours. I have a friend with a 1988 Malibu Response , he has over 4,000 trouble free hours on it with only routine oil changes and required preventative maintenance. However you could easily replace the engine with a 6L if you desire.

[dvskier]

[Mastercrafter]

6 L or 6.2 will not fit in the current motor box.  
 

I think you can still get a 5.7 through a Mastercraft dealer/Ilmor, but not totally sure. If you can get one, they are still about $15,000.  
 

It’s just a GM truck engine, long blocks are available all day long. Only other concern might be something like exhaust manifolds. They do have a lifespan, and I would want to make sure they are available if replacement was needed.

All said, if there is a will, there’s a way, you can put about any engine in that boat with a little bit of determination. 

[motoxr]

How many hours were on the boat?

[DW]

A GM 5.7 small block marine engine is not just a truck engine, there are a few marine specific items.  Short block - camshaft,  core plugs and you have to make sure you get a 4 bolt main bolt one.  A truck block can certainly be a great starting point.

[Mastercrafter]

2 hours ago, DW said:

A GM 5.7 small block marine engine is not just a truck engine, there are a few marine specific items.  Short block - camshaft,  core plugs and you have to make sure you get a 4 bolt main bolt one.  A truck block can certainly be a great starting point.

Oops. You’re certainly correct.  
 

My point was more or less that 5.7s are plentiful  

[GregHind]

3,500 hours already.  @motoxr

[motoxr]

Noted, that is a few hours for sure.

[BraceMaker]

On 8/12/2023 at 12:36 PM, DW said:

A GM 5.7 small block marine engine is not just a truck engine, there are a few marine specific items.  Short block - camshaft,  core plugs and you have to make sure you get a 4 bolt main bolt one.  A truck block can certainly be a great starting point.

That said I know of a few people who swapped in 2 bolt engines and didn't do anything but flush the antifreeze and swap over the manifolds

[HMan66]

I got a 5.7 long block from michiganmotorz.com. You just need to swap over all the externals.