350 Mag/Horizon B3 enough for '06 260?

[Scotto97]

Scotto, a few years back I had a lengthy conversation with a Merc technician. He said they recommend not maintaining over 3600 rpm for "more than a short time".

The reason your cruise feels better at 4100 is because that is getting a better speed for your hull. A 496 will produce the same speed at 800 - 1000 rpm less. I'm not sure how many of you have done engine swaps. Through myself and close friends and family we have done a lot with a number of boats. Going from a small block to a big block in the same boat is very enlightening. You get the same fuel burn numbers at given speeds, but with a motor noticeably working far less.

Todd, you mentioned maybe a desire for a 350 mag. We went from a standard 350 to a 350 mag in the same boat for a 70hp net increase. There was no perceptible difference. That was one of the first swaps we did. We quickly learned to ignore hp and look at the torque curve.

Great point - makes sense.
When I'm below 3500 RPM it seems I'm plowing and falling off of plane. I notice my speed falls off dramatically if I don't maintain at least 26 MPH. So with the Mag 350, I'm forced to either run at displacement speed (around 6-7 mph) or run at 3500 + RPMs.

Since I use the boat as an overnighter/RV (go to a spot and stay put) the Mag 350 is fine. If I was cruising long distances or towing more, then the 496 looks pretty much required for longer engine life.