360 AMC Oil Type Question

[DSFLY909]

Anyone know what type of oil I should be using in my 360 AMC? I was told 5/30, but I would like to get a few other opinions.
Thanks

[Jetdriver]

Im using straight 30wt. Seems to work just fine.

[Jet City]

5w30 is crap weight for a jet boat, once it gets hot your oil pressure will be far lower than with a heavier viscosity oil, jet boats are hard on oil. I would run nothing lighter than a 15w40 for this application, many guys favor 20w50 but I find straight 40 weight works best for me (higher pressure, less thinning, etc.). There is no harm in trying different weights, you will notice a difference in oil pressure under hard use, let that be your guide.

[waterslinger]

40wt or 30wt if it is cold were you live.
I love AMC motors gobs of power if it has a good set up. Any pics???