I have a 257 carrera deck boat stock 454 efi runs 55 mph and i would like to run 70 to 80 i have 10k to spend any suggestions ?

add 50K

IF I HAD 50K I WOULDN'T NEED SUGGESTIONS BUT THANKS ][/B]

share some of the details regarding the boat. I reworked a NeXt this spring 28 footer with a 509 CI and shorty drive when it left it was 85 GPS. Owner was very happy. However, it was over 10K close to 12K when done.

What do have to work with?

M3 Pro charger with match prop for the new power...??
It might be around 70.

I assume you plan on pulling the engine out? Is it carbed or efi? Do you have exhaust yet? If its an efi, heads/ cam/ and a ecu tune should get you some decent power. Call Marine Kenetics for that. Another option would be able to find a procharger with an intercooler in the swap shop for around $3K. That should put you in the mid-high 60's at least.

x2....

Load the boat on the trailer, you stay in the boat and have the wife pull it down the highway !!!!!!!!!! That's the only way that is going to happen.

You would need somewhere in the neighborhood of 200-300 horsepower to move from 55 to 80. Heads, cam, exhaust, gaskets, computer tune... seems like that would kill 6-7k easily. Add another grand for a new prop. I'm guessing low to mid 60s could be had for 10k. Will you pull the engine and do all the labor? The first 100 horsepower could happen in your price range. Assuming you have a Bravo 1? I don't believe Mercury puts this drive behind anything over 425 h.p. That may also be an issue. Good luck.

To safely run 70+ mph you really need full hyd steering. That will take more than half of your 10k, then you will need a bigger prop, then you will need to upgrade the drive to handle the added HP.........then, etc........