Twin Disc MG-5050A Marine Gear Transmission
I recommend:
Twin Disc MG-5050A Marine Gear Transmission, it is
THE way to go.
--10 degree output flange down angle is the most popular one to get.-- However, need to look at the application to be sure for you.
Bell housings are available for all the standard SAE one's - so for a Cummings I think they use a SAE # 3 bell housing.
Cummings are usually standard with right hand engine rotation, but check that too - to be sure.
You need to measure your propeller shaft angle to see where that is at as that is not easily adjustable since built into the hull & the engine mounting bed relationship to that.
NOTE: the transmission output flange needs to be set up by adjusting the engine mounting angle of installation so the propeller shaft flange & trans output flange meet at exactly same angle to bolt up.
Look at how much room there is to do modifications with the bed stringers & adjust the motor mounts as you want the engine to sit close to level, plus or minus a few degrees.
Rule of thumb is Engine needs to be under 10 degrees angle maximum from level. The closer to level the better. You usage may very with internals set up layout in your Engine room.
These transmissions input to output Ratios vary from 3 .0 to 1 for a very heavy & deep draft full displacement style hull & large big bite pitch slow turning prop and extend to down to 1.0 to 1, so need to do some figuring out what way to go there.
We will need more info to guide you as to which ratio would be best for your application. What else is needed to know is prop diameter & pitch, vessel size & displacement or Semi-Displacement style hull, type of usage, etc.
So probably expect your needs to be some thing in the middle like a 1.8 : 1 ratio maybe ?
These units are Super reliable, Work great & Last a long time.
Can't go wrong with one of these.
I will get the conservative HP ratings for this trans & post it soon below.
I have run this style trans in multiple boats over many decades of years of boating all over US waters with lots of over 300 HP running through them with never an issue.
Good Luck.
Alfa Mike
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