i have a 2000 wellcraft 330 coastal with 454 7.4L with 1100 hours. i am starting to research repowering her. the 383 mag 6.3L was recommended to me. What do ya'll think?? I was told my fuel economy would pick up alot. can anyone confirm this for me??? By how much you think. Right now i get .7 mile per gallon at cruise. Fuel economy is on top of my list of why to repower. thanks for the help.

A 383 will have to work a lot harder to get the same results as a 454 in turn burning more fuel. Just ask your wife if smaller is better.

I agree with Jeff. You could build some 460" (.030 454) with a small cam built for max rpm of say 4800-5K with a 750cfm carb on a dual plane manifold and it would definitely be more fuel efficient than the old ones you got and make more low end power for ease of getting on plane.

Unfortunately if you want better gas mileage, maybe refitting them with diesels? That might do it. Otherwise, maybe you should look into selling the boat and buying one with outboards.... the newer ones get pretty good cruising mileage... I think. Nothing related to performance boating is going to be fuel efficient. LOL

Smaller underpowered engines are not the answer, and JESUS .7mpg is TERRIBLE....

Also - you might want to check out www.thehulltruth.com - fair number of 330 Coastals over there and always talk of repower on that board. Probably not one member on here that owns one.....