I think I have my over haul figured out.
Right now I have and 1987 330 mag with 750 hours on it, It runs good and burns no oil. I has a new comp cam and peanut port heads.

here's what I'm thinking about doing. I have 049 oval heads with 1.07 intake and 1.88 exhaust valves. Doing some home pocket porting on them and maybe harded seats. Rebuilding lower end with Speed Pro hypereutectic pistions .030 moly rings. H693CP . 210 dome. Should be less than 9.3 to 1 comperssion ratio when done. Camshaft, still the comp 262h-12 adv. 262,268 @ .05 218,224 lift .505 and .515.
Everything else stock. Intake, carb, exhuast....ect. \

Boat is a 1987 Power play(Powerquest) 230 conquest. Weight about 4000 pounds guessing. Corsa captian choice. 51 mph on a good day Trimed up high as possible safe limit 4500 to 4600 rpms 19 pitch Mercury Vengance, Also have Marge Plus 19 but only revs 4000 so don't use much. Both propes new condition.

What should would I exspect? Is it worth the trouble? Only use the boat 20 hours a year or less, but maybe if thing would GO, I would use it more.

This would be a relativaly cheap rebuild and is within my buget. I need input if it's worth doing?

Thanks

Dan

I rebuilt the 330 in my 1989 24' Pantera a few years back.
I went with pistons that brought the compression up to about 8.6:1. I used a similar cam, maybe even the same one. Installed an Edelbrock performer intake and K&N filter. Added Imco stainless risers to the stock exhaust manifolds. I gained 300-400rpm and 3-4mph.
I know that a number of people install larger valves in the heads, but I think the cost is nearly what you can buy a better set of heads for. A good set of exhaust like Stainless Marine will also help a lot.

The compression ratio is good, and the 049 are good heads. I would caution you on home porting unless you really know what you are doing. You can do as much harm as good. What would really wake the heads up would be to install 1.88 and 2.19 valves in it. Also, your cam choice is very mild. You could step that up even with the Corsa system. RMBuilder on this web site can help you out with a good selection. Be sure to change your rod bolts to good ARP's. Align bore the block so that crank is turning nice and free. I am assuming you are running a Q-jet, so make sure you have some larger metering rods for the secondaries. Dennis Moore has a full list of rods in his BB Chevy Marine Performace book. If you got the coin, upgrade the exhaust to at least some good hi-po exhaust manifolds and get rid of the heavy Merc's. Twist it up to about 5000-5200, it will be OK. Good Luck!

I agree with Whiteknuckle. My cousin is using very close to the same Comp hydraulic flat tappet cams as you are (Something like 218*/226*) in his 330hp upgraded (454 bored to 461cid) engines and they made 461hp @5100rpm on the dyno with 8.6 comp ratio, junky lookin' large oval port GM heads that had some bowl work done to them and larger valves installed, and dual plane intakes.

Is it worth spending the money? Right now the engine has alsome power to 3500 rpms and 45 mph. gets out of the hole really nice with any load. But once it hit 45 mphs it take a long time to hit 50 mph. It feel like something is choking it off after 3500. If I go into a hard turn and cavitate the prop. I don't have to worry about over reving it.

thanks for any input

Any more input?

Is it worth spending the money? Only you can decide that. There are other alternatives, crate motors etc. I personnally liked the challenge of modifying my own engine. Remember, in performace boating there is very little cost effective things. Its not like a car where a little more power results in a noticable amount of performance. To make that boat go 3 MPH faster you need about 30-50 horsepower. What you do have going for you is the OSO board. There is a wealth of info on modifying the 330 HP 454 and everyone is willing to help.

Would this make it fun to drive? If it would, then it would be well worth the money. Right now I don't care to take it out much because it just don't have the power I think it should. My 211 Liberator with the small block would out do this thing.