OK I hope you guys can help me out here.

I'm looking to get some more power out of my motor its a 84 330 Mercruiser. The motor is all stock. What I can do to it to get more power from it?

The motor is going to come out this winter and be rebuilt. But for now I'm just looking for a few more HPs.

Any thing I do now I would like to still be able to use when I rebuild this winter. I am going to be uping HP to about 450 this winter.

Thanks Rob

If you do a historical search on here there are ton's of posts about building up 330's. Dyno and a few others built "330's on steriods". If you find these posts it will give you all the information you need to get 450 hp out of a 330.

What are you using for drives?

What exhaust are you running?...Thats not a bad place to start plus you will have to upgrade it when you add more power anyway if it's a stock type system.... then intakes, carbs, head work, bore.........Fred

TRS Drive with merc tranny its a singe screw

Everything is stock. Which exhaust would be a good choice for me? Also are there any proven heads that will bolt on? Or am I better off having my heads done.

If your 330 is original with the year of that boat, you probably have large oval port heads. They are a very good head with some port work and larger valves. If it has peanut port heads, they are basically junk and will hold you back with anything you do. As for exhaust, it depends what you spend. Many people like Stainless Marine for the money. Emi too. I run CMI E-tops, but they are more expensive.

How can I tell if they are the large oval port heads?

If you pull a valve cover, you can take the casting numbers and reference them. I think there are two different casting numbers for large oval heads. I don't remember the #s off hand (maybe one ended with 049?), but I'm sure someone here knows them. I would recomend Dennis Moore's book for some good information that is all compiled in one place.

Scott72 is right about the heads. 049 are the best of the oval port heads GM ever made. John Lingenfelter had them on some of his high pervormance street engines. The World Products Merlin oval ports are better, but the 049 can make 450hp with some work. Your exhaust needs help. An intake is worth 15-20 hp, your carburetor is fine, just needs minor mods to make 450. The cam must be changed. Iskenderian has one they make for me that runs great-has a little rough idle but very good power in a boat!! Talk to Ron at Isky. 323-770-0930 of call me 704-574-4020.