Exhaust manifolds

[crspang]

I am replacing a 1999 mercruiser 5.7 liter carbureted with a 2006 5.0 MPI. The current exhaust manifolds on the 5.7 are cracked. The 5.0 MPI has no manifolds with it but it had dry-joint exhaust. Can I use the non-dry joint manifolds with the 5.0 or do have to use the dry-joint? This will be a fresh water boat.

I'm getting conflicting information some I can order older style non-dry joint and some say I have to use dry joint. Plumbing difference?

 

[Scott Danforth]

Dry joints are a much better option

 

[crspang]

Also, how do I know if I need spacers? This is obviously my first foray into this.

 

[Scott Danforth]

You measure your riser height to your waterline. If the distance is less than 14", you need risers between the manifold and elbows

 

[crspang]

Ok, thank you for that.

 

[Scott06]

Dry joint is better, but especially if you are fresh water only you can use a non dry joint just fine. I did on my repower no issues and saved a few bucks vs dry joint. Just as mentioned above measure and determine if you need risers.

 

[crspang]

One more dumb question, how do I determine if I need 7° or 14°? Assuming I go with dry joint.