Here is the information link to the oil I used in my HDPI
http://www.amsoil.com/storefront/hpi.aspx and while some say it is expensive to use, wait till you see the repair bill for a blown power head
besides with fuel going though the roof, it just may "Pay" to switch in increased fuel savings from the lower friction and heat build up such oils provide.
I also used / use their gear oil for my lower unit which makes it shift easier and I hear less of a clunk noise when going into gear
https://www.amsoil.com/storefront/agm.aspx
And when I get more than 40 hours on my Honda 4 stroke (I have a blend it it now for break in) I will run it on their oil also. Now I should have had the break in process over with by now, but the Red Tide has been and still is, very bad in our area. So my boat (you know, that big hunk of plastic that was put their for me to mow around
) has been setting for weeks now (bummer)
Tight Lines!
Dave