Thank you Ryan.
As mentioned before I will test with air pressure.

I will take the heads of, take it apart and send it to a mechanic that can fix all of it.
I hope I can borrow a compressor to do leak down test before.

But when the heads have come of I maybe can see if there is any damage on the cylinder heads as well. I hope not.

This is the method I used on the rockers on my 496HO.

We don't need no stinken manuals, we got You Tube

The guy states "how to install a given type of roller rockers on stock studs on a 540"

The method Larry uses is only for the Raylar stainless roller rockers and his custom AFN nuts. The torque spec required sets the correct preload on the lifter. This setup requires stock/Raylar heads, rocker studs, cam base circle.

I run these rockers on my 496. They are very nice pieces and the engineering has been done for you. No guesswork and fit under stock valve covers.

Do NOT use the video method if you have stock 8.1 valvetrain and rockers. Use the spec alldodge posted. Although it does not specify, I like to go thru firing order and torque to spec when lifter is on cam's basecircle.

If I dont need to open up the engine, just fix heads for example.

Is there possible in some way to see what crankshaft I have in my engine, forged or cast, by just look at parts outside, wlywheel, contact or something?

Not unless u pull the oil pan to inspect. Only a few very early production run 2001-02 496 HO models were built with a Kellogg 5140 forged crank.

The stock cast nodular iron crank on the 8.1 platform is actually a nice piece and is fine to 600hp.

The Raylar rockers are nice pieces. That's what I'm running along with his blower camshaft. My rockers were all within the spec he wanted luckily. His rockers are torqued down fully like the stock rockers are. He just checks to make sure your're not overloading the lifter.

Okey thank you.
I have the Mercruiser 496 Mag from the beginning.
Serialnumber: 0M680267
Engine block number: 12558110

So it must be cast crank then..

Now when I have the engine half apart im cleaning my injectors and looking at my cool fuel system to get it cleaned.

I have some question about the cool fuel system on my engine though.

I have heard about the paint problem in the cool fuel system like we talked about, and like I linked to a youtube video some posts before.

But when I look at my engine, my system isnt like the cool fuel system that the guy on the video has with the paint problem.

My cool fuel system looks like this one, and are located in a plastic box on port side of the engine. #2 and #25 in the picture:





The guy on the video has this one, what I believe is located on the starboard side of the engine?
And is called Gen III cool fuel system??





My questions is:
can I prevent something to happen, or clean my cool fuel system in some way?
Or is my cool fuel system better than the other one?
Is there anything that can go wrong with my cool fuel system?
Is it called Gen II cool fuel system?
If there is something that I can or must watch over with this type of cool fuel system please let me know!

Thanks!

My 2004 496HO had the older Cool Fuel 2 system, which didn't have the paint issue. The 2 system also has an adjustable fuel pressure regulator from the factory. It also does NOT use that internal filter the looks like a disc. Looks like you may have a Cool Fuel 2.