Bill- I was under the understanding, that the Cummins and Iveco were the same long blocks, but marinized by the respective companies. I thought the 5.9 Cummins and Ivecos were identical, as well as the Iveco and Cummins 6.7's. Guess I may have been wrong; where did you get your information?
As far as experience with Iveco engines, I installed their 5.9 liter (they call it the N60) that was an A2 rating of 370 hp. It performed impressively and the power to weight ratio is great. Very strong, fuel efficient, smooth, etc. This next boat I'm starting on in a week will have the 6.7 liter N67 A2 rated 420 hp, which is probably the same exact engine that will be going in this new 33' Young bros.
Brian, Cummins and Iveco sharing the same 6.7 block is "100% dock talk" spurred on by Fiat/Iveco dealers etc., to increase sales. The Fiat/Ivecos are good engines, maybe expensive on parts and service.
A couple months back I posted a question on boatdiesel about the "new Cummins 6.7" and whether it was an over bore or beefed up 5.9.
I got a couple of responses back from UK based Paul Foulston, not sure if he retired, a Cummins diesel design engineer.
His responses:
"Not a simple overbore, completely new rear gear drive block, strength not compromised, bore stroke 107 x 124mm.
As to the rest I can say no more!"
Paul
This is his response to a post by a forum member about the new Cummins QSB 6.7 being the Iveco 6.7:
"Must be the Iveco 6.7"
No, No, No! 5.9 is 102 X 120 common to Cummins and Iveco.
Iveco, increase the bore to 104 mm and offset grinds the 5.9 crank pin to increase stroke to 132 mm. More fresh air inside the engine at the expense taking some ´meat´ off the crank pin.
Cummins approach entirely different. Totally new block allows meat for 107 mm bore. If you have ever seen inside a 5.9 crank balance weights come within whisker of the camshaft. Jerl Percell at Cummins re-designed crank in area of balance weights in order that they could get throw of 126 mm WITHOUT compromising crank bearning area and still clear that pesky cam.
The whole thing was then patented to stop the Italians getting their hands on it."
Paul
PS Think this answers Bill D I´s question"