Re: 7.4L- Should I bore it out??
tell that to Mercury who has been running 502's as their 525hp for many years, and the 425hp since the demise of the 8.1 in 2009
Mercury uses them because that's what Mercury can get their hands on.
525EFI's are Mercury Racing engines, and not mass production engines.
The current 8.2 engines are 430 horsepower, in the form of the 8.2 MAG
Interesting to note that the 525EFI engines are rated at the crank, the mass productions engines are rated at the prop.
Volvo decided to not use the 8.2 available to them as well, and they are getting 430 horsepower out of the 6.0 liter engine.
Other than that. 502's are heavy, have Siamese cylinders, they do not make the same torque as a 496, and still to this day have reversion issues because they have to run such a hot cam to get the kind of power they are looking for out of them. You should see the amount of 02 sensors that get replaced every year because of it.
The 496 is/was a bit lighter, made more torque down low, got better fuel economy, and does not have the reversion issues. And if you take 2 identical boats, and stick a 496 420hp and a 502 MAG 430hp in the other, and everything else is the same, the 496 is going to outperform it. The whole point of the 496 from the get go was to have diesel engine torque in a gasoline engine. The 502 is just a punched out 30 year old big block.
Other than that, there is still a bit of NOS 496's out there, and you can still get new 8.1's if you want to, and however you want it, through PSI.
Of course these are just my opinions... And your all welcome to your own. =)
