What is your budget?
Have you tried labbing your prop?

Yes, net 15-20 HP more than stock HO maybe 25 but I didnt see huge results and I had head work.

You have to understand that "just one" of these things wont net any real HP. You have to do all of them to get some HP and its still negligible. The only thing you have going for you is that your hull will respond better to more HP than mine did...

If you think you'll get 470 HP with bolt ons for the 496 HO or something close you are dreaming. I played the game, lost the battle but won the trophy.... LOL

If you want the bare bones but GOOD HP, buy his heads and pistons. Use that as a base and go from there. Just the heads with new pistons is probably 485HP then build from there... UP to 625 HP or close...

I don't really have a budget in mind right now. I was going over the idea of upgrading the 496. IMO I'm not sure if it is worth putting big money into the stock block. By the time I buy Raylars kit and do all the machine work and reassemble, I am way over 10k not counting exhaust. I don't know what the longevity will be than and I am just about maxed out for future upgrades. I also don't like the fact that I can't personally tune the ecu. I would probably switch over to something that I could program.

I was just thinking of adding a few more hp right now. I thought I read from Ray that the stock intake was done at 4000rpm. That's why I was wondering if the intake would add any hp in the upper rpm range. I might try to install a vac guage after the tb to see if the engine is drawing vacuum at rpm.

I am pretty happy with the 496 performance on my boat. It will usually run 69-71mph. Like everyone else you get used to it lol. I tried different props and have 2 right now that I like the best.

I'm am kicking around the idea of repowering, but I know deep down I should just leave it alone and enjoy the decent gas mileage and perfect reliability. I have been playing with cars for 25 years and know about increasing hp. My current weekend car is a turboed Mustang that makes 900hp reliably. It took me 20 years to get it where I want, only remove the valve covers once a year to check valve lash.

I had whipple do a stage II flash on my 496 mag (non-ho) and it woke that motor up. While I don't think it did much on top end, it mad a huge difference in low-mid range torque. It is tuned with the 120 T-Stat to run 92 Octane. However in Michigan with the fairly cool water temps I have gotten away with 89 non-ethanol without any issues at all. HOWEVER, I do not run hard. I almost always have my wife and daughter on the boat, so we cruise in the 3500-4000 RPM range. But that is where the biggest difference was after the Stage II flash.

I don't think the tune is for me. I'm more interested in top speed upgrades. I always baby the throttle down low to be easy on the drive. I also don't get soot over the transome. For 10-15hp I'm better off leaving it stock.

Thanks for the info everyone!

Your on the right path.
By the time you buy the Raylar kit, put forged pistons in it, and pay to have someone tear into the motor, you could save all that money, sell the already good running 496, and buy yourself a 500 EFI, 525EFI, or buy a 540 and be done!