i have a 32'' carver boat right now w/ twin 350's in it, just wondering what would be involved in putting a 24valve cummins in their, i know its big money if i went w/ yanmars but its easy to find used cummins. any help would be appreciated.

 

Moved this to the Cummins Conversions forum for you.

Sounds like a cool project. One thing to keep in mind though is the increase in weight, as a 5.9 weighs over 1000 lbs.

 

aside from getting new props that are set for the engines sweet spot, you will need to repaint your waterline, them babies will make er squat !

 

I would think that putting a 12 valve in would be the better motor to swap in because it will take almost no wiring to have them run, were there will be quite a bit more with the 24 valves.

 

^ completely agree. Install the 12v, less wiring. I'm installing 2 6LP-STE Yanmars (900+ lbs) now into a 35' Phoenix...which had 3126TA Cats (1150+ lbs)...lots of work.
Yep, you'll need to get the props re-cut
figure out the wiring
make sure the trans will match to the motor

 

The Cummin 6BT (5.9/6.7) is twice as heavy as a Chevy small block V8 - so you may want to go with just one; or consider a pair of Cummins 3.3; which weigh about the same as a Chevy small block V8.

You may also want to wait for the new GM 4.5 litre V8, which will be the same size as the small block, and not much heavier.