496 to 525 swap?
 

I have a 496ho and of course I'm looking for more HPs. Rather than try one of the few upgrades avalible for mine I was thinking about a swap to the 525. This is in a 28 Thunder that weighs in at about 4700. What kind of speed might I expect with the extra horsepower? I know it isn't a cheap route but if you figure the value of mine it might not be to bad. So now the question, what is my freshwater, 170hr 496ho worth?
Thanks

The nice thing is, the 525's are dynoing around 540hp at the crank, so you're picking up about 85hp at the prop. Probably good for 6 -7 mph would be my guess.

that would be 115 hp at the crank

The 496HO is rated at 425hp at the prop (455 at the crank). That's a difference of 85hp.

Now, if you are considering that Dustin Whipple has said that he typically sees 410 - 430 hp at the CRANK on 496HO's, then you're right that your talking about 100 - 130 hp.

Hey boatfreak,
Sounds like you are getting ready for some Cops runs this summer. I hate the price of Mercury blue but it's extremely reliable which is worth everything when you have three good months out of the year to boat. Have you found a good price on a 525 yet?
Dan

425 at the crank

http://www.offshoreonly.com/forums/s...threadid=65289

I don't care what somebody's misprinted manual says. Merc advertises the 496HO as 425hp at the PROP. Check their website, call them up, check any authoritative source other than those stupid service manuals where they can't print anything right.

Now, as I said, reality may be that the motor dynos lower than that, as Dustin Whipple suggested.

why not super charge it ?

I just don't believe it is a good engine for a supercharger. My thought was if you spend $7,000 to charge it and have a problem or even worse major failure then you have pissed away a good engine and your 7 grand. On the other hand if you take that money and a little more to it and switch to the 525 you have a far better engine making that extra one hundred horse, great reliability, and maybe even increased the value of the boat.

checked website all hp #s for all motors at the crank