Mercruiser 496 HO Cam?
 

Where can I get a 496 HO cam to replace my 496 Mag cam with? Can you order them directly from Mercury or are they way overpriced? Not having much luck with the Googles...Sorry if this is the wrong forum for this.

You could probably contact Raylar performance (they're the 496 gurus) and I would bet money that they have many excellent condition takeouts that they would sell you. They're also a member on here and may chime in.

Not sure on purchasing an OEM. Good luck

I forgot who made those cams to order direct off of them. Above post is likely correct about his info, I would try them or call Dart as they could possible tell you the source to get them or you could spend some real dollars with Merc. Also you will need to remap the PCM and drill a hole in the throttle plate, forgot what size. There was one thing else to do but can not remember it for upgrading the MAG into the HO. Maybe someone else will chime in,

Also calling Dart they can tell you some other ideas to hot rod your 496. They sell Gen VII / 496 parts and upgrades as well.

cmkworm,

The HO cam:

224º/233º @ .050” (222º/232º)
.300”/.300” Lobe
.510”/.510” Valve
114º/115.5º

We grind them on the 8.1 C swap core.

Bob

Prety sure you listed everything. Cam, PCM remap, larger air bleed hole in throttle plate.

[ATTACH=CONFIG]529880[/ATTACH]My $.02 dont do it for the 50 HP - A different cam profile without changing the springs is a little risky. The 496 springs are already weak as the little springs in a ball point pen. Then you change the cam profile and they are working differently (this alone is suicide). You drop a valve and this happens. Upgrade the pistons and do it right or you will regret it...

I have a little experience in toasting 496's :)

Change the springs, upgrade to roller rockers and you might have a chance.

Totally agree with KA here about this one. I stopped doing the MAG to HO convert years ago because really when you look at it on the water 3 mph to maybe 4 max on a good day. Some boat owners did 'nt even see that improvement and wonder why they did the HO convert to begin with.

IMO spend your money on props and maybe take a good look at the weight of the boat and stuff on board. Either do some repositioning (balance) or take some weight out of the boat.

You are sooo right. "Blueprint" your boat. Take all the crap out and I mean all of it. Lab the prop, use a good high quality synthetic 15-50 like Amsoil or whatever. Use a good synthetic drive oil, plugs, make sure your spark arrestor is clean. Then, add all your crap back in and see how much it slows you down. :)

Forgot FWIW the heads (springs and rocker arms ) are all the same from the MAG to HO on stock app. Like KA said the stock springs a not the best out there.

LOL, you sure are being nice today. Call a spade a spade, the stock springs are junk. They are like 50 pounds seat pressure - literally.

You might be able to pull it off with a new cam, reprogram, new springs and roller rockers. But the big turd in the room is still the cast pistons. When you get to the power range of the HO you are spinning it 100-200 RPM faster than the MAG. Then, one of the lovely brittle cast pistons takes a crap. To get decent HP you need heads. The risk reward for 50 HP isnt too great.

It looks like this in your oil pan if you are wondering. :) (yes, that was a piston)


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