Rage,
A few things that are going to pertain specifically to you Is the 4 ball wear test, Kinematic Viscosity at 100*C, and the Viscosity Index. The Kinematic Viscosity at 212*F is going to give you a good idea as to the thickness between the pison/rings and cylinder walls. Basically on this test, the higher the number the better. The Amsoil MCV is 20.56, the Amsoil RD50 is 17.5, and the Mobil 1 V-Twin is 21.04. The Viscosity Index is going to help you make a good determination of how well the oil is going to maintain viscosity at high temperatures. The Amsoil MCV is 156, the Amsoil RD50 is 162, and the Mobil 1 V-Twin is 145. The other thing that I would note is the 4 Ball wear test. The 4 ball wear test is a good indication of how well the oil is going to protect your internal parts from wear. The Amsoil MCV is .373, the RD50 is .47, and the Mobil 1 V-Twin is .395. Basically the Mobil 1 is a very solid oil, but in your case since it’s harder for you to find, you might want to consider switching to the MCV as that’s a solid performer. Depending on how much reading you want to do, here are some fun facts for you.
http://www.amsoil.com/lit/G-2156.pdf

Hey minxguy, Did you get my PM?

Bill

[QUOTE=minxguy;2921079]

Lots of good info here. I am running merc 25w-40 now. Will i see more or less oil pressure with m-1 15w-50 gold cap hot and cold?? Also have the option of runing chevron delo 400 straight 40wt. oil. what would be your choice???
02 496ho's 180 hours

Thanks

You're comparing apples to grapes. The Mobil 1 is a full synthetic and the dello is a dino oil. I would run Mobil over the dello oil. Oil pressure shouldn't change much, it might go up a little bit with the thicker stuff then your engine was designed for. My 500 EFI wants to run the 25/40, which is why I run this, which is still a 40 wt.
https://www.amsoil.com/storefront/wcf.aspx

In theory, you should see higher oil pressure cold with the 25w40 and higher pressure numbers with the 15w50 hot.


Ken

-Synthetics do flow better when cold vs conventionals.

-Now a 40wt being less viscous than a 50wt will run cooler as a heavier oil actually causes more friction.

-A rule of thumb is to use the lowest viscosity possible.

-Having said that....these engines are stressed to the max...a synthetic 25W-50 or 15w-50 ought be fine.

Amsoil's 15W-40 Marine is great too!

I should explain why i compared these oils. I know one is syn. and one is not. The reason i asked about these was more for the viscosity. I can get through work (for free-part of my benefits package) m-1 15w-50 gold cap, delo 15w-40 or delo straight 40w hd . my main question is what weight would you run in stock 496ho's. the only reason i am not using merc 25w-40 is because these oils are not costing me anything and i think merc oil is $23.00 a gallon now and we can not buy it through our supplier at work. I am also running wix 51060 filters with no issues so far. also what amsoil drive oil do you recommend, the 75w-90 marine gear lube or the servere duty oil. My boating climate is 50 degrees or warmer(northern cheaspeake bay)

thanks again, jeff

If you can get the Mobil 1 15w-50 for free, then get it. It is hands down the best of the three. Now for the gear lube, get the AMSOIL 75/80w-90 Marine Gear Lube.

I would run the Mobil 1 also. I do run the 75-90 Marine gear lube with my 500EFI.

[QUOTE=minxguy;2921079]Ken,

Did you get my PM to you with my Email address?

Is there a problem with sending the two noted oil analysis?

I am definately still interested.

Bill