Power Upgrade Suggestions

[RJBBC]

We have a 2000 259 Convincor w/ modified 454MAG (461HP/514lbs/TQ). We recently blew a head gasket and are looking to repower. Still not sure why this happened, cylinders 6&8 have little compression and the gasket has been compromised in that area. Heads are coming off next week. The engine and stock B1 drive have 275 hours. The boat is equipped with hydraulic steering and HP tabs. The boat is used for family recreational boating. I would like to stay NA unless someone can make a convincing argument. Should we rebuild what we have? Rebuild what we have and change the displacement with stroker crank? Fix the motor, sell it and buy a 502 or 540? The power goals are 550HP and 600lbs/TQ. I think we can get a couple hundred more hours out of the drive if we limit the power to the stated goals. Any ideas or suggestions? Can we get 550 reliable HP for 10K utilizing the parts that we have?

[RJBBC]

Originally Posted by RJBBC

We have a 2000 259 Convincor w/ modified 454MAG (461HP/514lbs/TQ). We recently blew a head gasket and are looking to repower. Still not sure why this happened, cylinders 6&8 have little compression and the gasket has been compromised in that area. Heads are coming off next week. The engine and stock B1 drive have 275 hours. The boat is equipped with hydraulic steering and HP tabs. The boat is used for family recreational boating. I would like to stay NA unless someone can make a convincing argument. Should we rebuild what we have? Rebuild what we have and change the displacement with stroker crank? Fix the motor, sell it and buy a 502 or 540? The power goals are 550HP and 600lbs/TQ. I think we can get a couple hundred more hours out of the drive if we limit the power to the stated goals. Any ideas or suggestions? Can we get 550 reliable HP for 10K utilizing the parts that we have?

Ended up doing a valve job and putting the motor back in. Went for a water test yesterday and the boat ran great. Maybe putting a Whipple on this motor would be a good idea???

[Vinny P]

Hey Rob,

Good to hear that things worked out. Personally, unless you can 100% trust the person who maps your ECU, I dont like the idea of adding a Whipple to an EFI engine. Some guys here have a system where they can map the ECU themselves, but its not a Merc ECU. Ofcourse, unless you are real careful, you know what happens. I still say thats what ate your engine last year. Maybe I am living in the stone ages, but I prefer a good carb., easy and simple to get the fuel correct.

BTW, forget about that stock Bravo 1 with a Whipple. Sell it while it is still worth something and get an Imco or an XR.