360 to 450... may gain 2-3mph on typical 24ft boat?

I gained a solid 4 mph on my 24 Outlaw.

Yes I am, but not for boats......yet. my trucks are another story. Thanks for the response and PM's Griff. I'll post back to this thread when the build is done.

Your miles ahead of a lot of the 454 build threads as you are starting with a mag motor, so you have a better crank and rods already. You can also look up the specs of the Merc 420 which was a 454

Always best to copy something that is known to work well. You may lose a little of the bragging rights but it will save you lots of time and money, especially on a boat eng.

I like the idea of building up a "fun" eng then pulling your orig eng and storing it when it's time to install the "fun" eng. If the fun eng takes a dump, you can swap in the orig eng back in over a weekend and be back on the water quickly. Otherwise, you'll most likely be done for the season. Also, most buyers like to see all orig parts when the time comes to sell.

Parts ordered. Also going to mill the heads a bit. Going to be a month or so before work starts on it. Kids want to play/wakeboard/skii/tube. Likely going to get this project of the ground early fall. Boating at 6000-7000 ft sucks.