4 bolt mains / steel crank etc on 496 mag & HO

[skipjack26]

I can't seem to get an answer from my mercury dealer as to whether the 496 mag and mag HO both have 4 bolt mains / forged steel cranks and the 7/16 in rods ??? They say it has been difficult getting this info from Mercury. I called Mercury this morning and they said they do not have that info available through their call center and recommended I write my questions down and ask my dealer to send them to the "dealer hotline" for answering.
I understand that the HO version has different heads ??? Any info would be appreciated.
Skipjack 26

[James'SS-24]

I just bought the merc service manual for my 496 mag. It looks like the only difference between the two is the crank, cam, throttle body, and ecu. I found that out by looking up some of the parts on mercruiser parts express, a web sight by Bam marine of Florida. Both engines have 4 bolt mains and roller cams and from what I can tell all of the rest of the internals are the same. There was a good article about the engine in Hot Boat magazine a couple of months ago that will help also. I sure like how mine runs! http://free.***boat.net/ubb/biggrin.gif

[BLOWNDRAGBOAT]

They are pretty much identical as far as forged crank,big rods,and 4 bolt mains. I have been told as a rule of thumb, any mercury engine rated above the 360 hp range has 4 bolt mains,steel cranks and bigrods. The only MAJOR differance seem to be the heads and induction system. The lower rated hp engines such as the 330 hp/454 have oval port heads. The higher rated models such as the magnums and the 370hp TRS motors have rectangle port heads. The carb models with a mark IV block used hydralic lift cams but not sure if is all mark IV's. I think ALL the higher hp rated engines using Mark V and Mark VI fuel injected engines use a hyd. roller cam. Of course this is only on the fi units. There mercury SC series are a different story. Hope it helps.

[BLOWNDRAGBOAT]

I am also told that they are in development of a Y block. That would be pretty trick.

[skipjack26]

thanks for all the info. this is exactly the info I was looking for !!!

[sea buddy]

I suggest you confirm with another source that the two new for 2001 496 Merc engines share the same part number crank and other parts. That is not what I understand.

[rivercrazy]

The 496 mag HO has a forged steel crank. The 496 mag does not.