I doubt you are going to be able to get another 100 hp without loosing reliability and some serious engineering, but you will need to talk to Cummins.
Instead how about having the injectors checked to ensure the spray pattern is accurate and the pump checked over so that the engine is back to producing its original hp.
I agree, not the right choice you could advance them, for some xtra oomf, but you'll be putting out black smoke, and thats not the the way the're meant to run, they will run hotter too 'specially if they have blowers on them You would need to upgrage the cooling ability, but would end up over stressing something else
I take it that that's the "marinised" version of the "B" series fitted to my trucks? I think mine are rated at 240 continuous...so 315 ain't bad in the first place....
Jono, could well be, I have been looking at Perkins and Ford (Lancing) but they are different base engine blocks. However they also get 300 hp from 6L for a marine version. I am not sure taking them up any more will a happy event as Bigmuz7 says and they are 1992 engines, so could be down on power from original. However with a check over of the injectors and as Eios says loose some weight then the boat could be transformed. Should know spent two years adding things to the Pacific and watching the speed come down
I have spoken to Barry this boat has a 2000l fuel capacity. When Eios got the weight the concealed tank must have had fuel in. This boat should be 3500kgs dry weight
If you do a search for cummins diesel lpg you will find loads of stuff - plenty of companies converting trucks to run on the stuff - mainly to save money on fuel but they do claim upto 25% power increase with much smooother running.