CUMMINS 400

[Craig Mac]

I found this build thread on another web site---does anyone know the boat ?

First time I have seen these motors in one.



http://www.spearboard.com/showthread.ph ... boat+build" onclick="window.open(this.href);return false;

[Bruce]

Nice pic of buddy boy Pat.

My guess some kid posted those pics, but who ever it is has no clue what they have or is being done. He's right on one thing, they are Cummins. And they are QSB's.

[IRGuy]

800 HP in a B31?

Really?

[bob lico]

Bruce they sell the aftermarket split exhaust manifold for both the QSB series and 6bta mechanicals for twin turbos . I would not be running that engine for for too long at 3100rpm and he going have to dock with trolling valves or be real good at docking at 12 knots.to turn 40 knots plus he has to carry a nice pitch on props , 5 mph zone are a real bitch one engine in gear at idle 7 knots.

[Tony Meola]

Bob

Looks like he had the same idea as you for the bridge seating. Just did it a little differently.

[bob lico]

Tony he e- mail me a long time ago and I explained.i should clear the air in regards to trolling valves ,they are not " magic buttons" you press and your speed problems go away.they are not made to shift from forward to reverse like docking.even with the rudders you need both engine to maneuver at dock.he will not make friends coming in at 12 knots to a restaurant on the water especially when he has menaceing bow pulpits looking at you 34' apart while he makes U turn and he has to slide into a tight dock space at restaurant.he did a beautiful job on the restoration .

[Bruce]

Nice pitch is an understatement. On the 31 I put a pair of QSB 370's in, it had prop pockets.
I still just fit the right size props on with pockets and no trolling valves keeping full load to a stringent Cummins requirement for warrantee.

On the aftermarket manifold, yes. But the one pic of the engine its the stock manifold and unless he's going to eat the warrantee, Cummins would never certify with aftermarket parts bolted on.

[PeterPalmieri]

Is there additional air intakes that I don't see?