Do you think 625hp is doable and a bunch of torque that should get thing moving and probably stick with the 239/247 cam or smaller?

Those heads are way to little. I ran them on a 439, and they were an awesome head. On a 540, it would be one of the last heads I would pick, and no way you're going to make power to 5800. Those heads are hard to find used and you could sell them at a premium due to that. Why not sell them and get the proper head? 265 for a 540 IS NOT the correct head.

If monster torque is so important, why not just throw a Caterpillar diesel in your boat?

Thanks for the advice do you think bigger afr oval or the 325cc square

They're quite a few lengthy threads here about optimal heads / carbs for a 540. Whether or not to even use AFR is likely to be a lengthy discussion.

The 290 and 300 ovals, 305 and 315 rectangles are all great heads. I'm not an engine builder, so I'm not suggesting anything other than the 265 is just a little head, and it was designed for a 454. A 540 is WAY bigger than a 454. Say it cost you an extra $900 or less to do it right, then I would do it the right way. IMO you are leaving a lot of power on the table with that tiny head. If I was building my 509's from scratch I would be running either the 290 or 300 ovals.

Wow I agree with endevour89 100%
:noevil:

I got a set of iron 502 heads i'll trade you for them...hell I tried.

I agree with the above. 265 , with a 2.19 valve, is gonna limit power. You'll make some big low rpm torque, and lack upper end power. It will allow you to run a really tall pitch prop, add some extra stress on your outdrive, and probably accelerate like crap, since it will be like running a 3.08 rear end, vs a 4.10 rear end. Theres a reason nobodys really running diesels in FAST offshore boats.

Thanks for the help guys i think im gonna swap them for 300 ovals or 305 squares any good cam ideas for 5600-5800