I have 496 Mag HO's in a 32 Sunsation. I had to have the pushrod recall done at 7 hrs. I have 70 hrs on the motors now and after 1 year they have been flawless. I boat at elevations that range from 500 ft to 4000 ft and the altitude seems to have little effect on horsepower.

As Dman2, wms, vyper340 above have said, I just cracked 250+ hours in just 12 months. Like Vype said, no salt water in the block. As far as the HP500's are concerned, they're gonna be history soon as there's just not enough juice over the 496 (470 -vs-425) to warrant the money and the headache of the extra saltwater care. The 525's are the **** over the 496HO if you're gonna dole out well spent cash for a significant upgrade. Other bennies I have found....Great torque over the 502, what I consider excellent fuel economy relative to the 502, and i figured out i really didn't have to spend any money on the K&N filter....:D

Rick

You really think the 500 will go away ? I am not so sure. 50 hp is 10.5% increase in power. That is noticeable in a boat. It is also more than the 525 over the 500. AT claims 8 to 10 mph more with the 500 over the 496. And man, those chrome headers and blue plenum sure look good under the hatch. Merc has a nice spread in the ther hy perf. engines with the 425, 470, 500. And remember, not everyone boats in saltwater.

496 HO 425 hp 5 year warranty $12000 fresh water cooling !

500 HP efi $21000 1 year warranty raw water cooling

Have to agree with Vyper, How long will GM continue to supply the blocks to merc?. The aftermarket will forced to focus itself on the new engines, so resale could become a mute point!. Ahhhh.... technology.
My issue was the $25K premium, 4-6 mph, not!

My02

When I ordered my boat from Baja, I wanted to get twin 502’s but I was a month too late. Baja had used all their 502’s so I had to get 496HO’s. At the time I was upset but not any more. I think these engines are great when compared to the 502 they replaced. On my boat, HP500’s would have gotten me only 2-3 mph more and would have been an extra $20,000.

As Donziman 2 stated, my new PQ 340 has the 496HO's in it. So far so good.

My old 2000 PQ 280 had a 502MAg in it and:
It used oil, had to be pulled out of the boat (twice) for oil leaks, the 502's manifold / risers will all eventually leak, thermostats consantly getting sand in them due to low water pickup, rust stains on the transom, etc.

When Donziman2 & Reckless 288 bought the new 496HO's; I paid close attention to any issues they may have encountered. Plus the way Reckless runs his boat, if there were to be any problems, he would be the most likely candidate for problems. Both had zero problems. So on the new boat it was 496 for me. All the 502's issues have been resolved.
I know have over 60 trouble free hours on each motor, and I hope it stays that way!!!

If you want more power than the 496HO, I too think the new 525 is the way to go. It is kinda like a 496HO with MORE POWER!!!

Whine from flame arrestor?
 

Anyone else experience the "whine" in their 496's? Apparently not all exhibit this. I would guess a K&N will fix the noise.

No "whining" allowed. You may want to look at the quality and fit of your engine hatch, or where your vents are located. I don't want to hear anything but exhaust from the back of my boat.:D

Merc gets the bolcks from GM parts. See recent Powerboat Mag article. The 525 uses the 502 block. Have you seen the premium for the 525 over the 500 ? Check it our before you totally poo poo the 500.

Hey the 496 is a nice motor. It does not and will not have the same resale as the 500 EFI. And 50 hp is a bunch. Sorry if you guy's are only expecting 2-3 or 4-6 mph gain. I think an 8-10 mph gain is pretty sweet. Which is what we were told was the difference. Plus, if you really want to make some power, the 500's have better internals to upgrade with a supercharger.

By the way, where did the $25,000 upgrade cost come from ?