I am aware that Powerboat Mag did a test a few years back on the 260 and came in with top speeds @ 72 w/496 mag (non-ho). THis test was of course in salt water, and I am sure a light load of fuel.

I boat in Fresh Water and have a 2003 260 with a 496 mag (non-ho) with a Bravo 1 26 pitch prop. We have 2 group 31 batteries, and 1 group 27 battery, a fairly heavy 12" sub mounted up front (behind the port-a-potty). So obviously hitting that mark of 72 would be a tough stretch. However a few weeks back I had Whipple do their Stage 2 Flash on my PCM. Today I was out by myself with 3/4 tank of fuel and hit 69 mph, It was still climbing, I think it had 1-1.5 mph left(motor has 330 hrs). I am sure if I took the subwoofer out of the front and a lighter fuel load, and pulled the 2 group 31 batteries (75+ lbs each) I would have seen much better numbers. But I think 69 MPH (GPS) is a pretty respectible number considering it is essentially a stock 496 mag (non-ho) in fresh water, with at least 200 lbs of stereo equipment.

Just figured I'd post my top speed results after the Whipple Stage 2 Flash. Before the flash I was only able to see 64-65 GPS (previously it had the factory flash, which was casued an overly rich condition).

Did Dustin have you do the 120 thermostat?
Speed sounds about right to me.
Do you still see soot?

Yes I did the 120 T-stat, and yes I still have soot..... Dustin told me there would be some soot, becasue of having to run premium fuel with the Stage 2 tune. Think I am going to try a different (longer) set of exhaust tips. I think a lot of the soot is being cause by a "Vortex" effect under the swim platform. I plan to replace the FIberglass platform with a tubular platform over the winter. So hopefully longer tips and a tubular platform will help reduce the soot. But even with the soot, I love the power and mid-range torque the boat has now.

My boat was tested in the 2005 Poker Runs America Magazine. Volume 8, Number8. Said it ran 74.3 with a 496 Mag. I only ran it one time with that engine. I didn't know how to drive it very good at that time, so I really don't know for sure. I think I saw 70-72 on the dreamometer. I would think you should be able to hit 70-72 GPS if you lighten up that stereo a bit.
You may have a little bit of difficulty pulling off the swim platform. I tried to take off my swim platform to make it easier to work on shortly after I bought it. I unbolted it and jumped up and down on it. It didn't budge. The 5200 was holding strong. I didn't mess with it after that as I didn't want to mess up the fiberglass.

I have planned on the 5200 tearing the transom up a bit. That is why I am having a friend of mine who owns a Fiberglass repair shop take the old platform off and install the new one. He will do all repair and paint work necessary. I also have a few small cosmetic areas that will be addressed at the same time. Not sure if I want white powder coat or red. I think the color will be determined by the stlye I go with. If a tubular platform like on the Baja Outlaw, I think Red. But if I go with one that has more flat surface, like I have seen on Cigarettes, I think it will get white powder coat.

is there a big noticeable difference in performance wise between the mag and Ho ..i know it's like 50hp difference, but is there a big difference between the two on the top end

I have the red tube on mine and get lots of compliments on it.

Hate to hi-jack this but me and my friend both have Velocity 26's with 496 HO's and discovered that tips with flapers cut down on the soot big time. Most of it it from put puting and the fuel on the water staining the aft end.

Any other mods to your ride? Still have the plates in the risers?

My tips do have flappers, but I think they need to be longer. The plates in the riseres went away when I went with the stage 2 tune....

I notice most of my soot comes from running the boat over 3500 RPM. If I cruise at or under 3500, I have a little amount of soot, but when I run in the 4k range, even for short 1-2 minute periods, this is where I get a ton of soot........

What is your fuel pressure?
My electric gauge read low making my presure high.
When i brought it down to what Dustin wanted it made big differance.