I don't want to beat a dead horse. I searched and can't say I know the answer.
Question is Steel or Aluminum? I have a Bravo and noticed the coupler is bad. I understand alignment. Do I want a aluminum or a steel coupler, which is best? I have read some say that the aluminum is better. I will have a built engine in front of it. Thanks for your thoughts on this.

Ayuh,..... The Spline piece in the center of All of 'em, are Steel,.....

I believe that Merc used the alum coupler up to 400hp and the steel one over 400hp.

They all are now? Bondo

I have heard they have different snout lengths.

They make a short aluminum, short steel and a steel one with an extended snout. I see no advantage to the extended one, it has the same amount of spline engagement as the short one and it makes it harder to install the engine if you have cable steering or are short on room.

will the short one still seal on the third o ring. Any chance on part number or what the short one fits? Thanks

A drive guardian is a very nice upgrade if you are making some power

8M0098795COUPLER ASSEMBLY, Engine - Short Aluminum Hub 8M0098797COUPLER ASSEMBLY, Engine - Short Steel Hub 8M0098796COUPLER ASSEMBLY, Engine - Long Steel Hub

thank you!