Hello fellas,

I have a bit of an off the wall question for y'all. I have a 94 7.3 idi diesel but what I wanted to ask you fellas about was that I was getting ready to use my truck to go pick up a boat that I may buy. The boat is an 89 Donzi Regazza 460. What makes these boats so special is that they are powered by the Merc 460 which is essentially the ford truck version of the 460 Ford big block with a wide power band cam in it. I figured if anyone in the world would know about these engines then it would be you guys. What can you tell me about them? What are the weak points of this engine? Is there anything I need to know about right off the bat?

I know that they don't get very good gas MPG and I am not really concerned about that. I also know that Edelbrock makes lots of aftermarket parts for these engines that are capable of turning out BIG hp.

Thanks for any advice in advance

 

They're stout engines that drink a lot of gas. Not anything incredible, not much bad though either.

 

Eh, I beg to differ. The 460 is a monster. Lots of guys use them in boat racing. Check out 460ford.com there are guys building earth shattering torque monsters for their boats. The 460 is cubes and more cubes, so yeah its awesome and yes its VERY thirsty especially in a boat. Plan on pickin up a second job to affor the gas for it.

EDIT: Sorry, I just realized that boat was a cruizer, not a jet boat so yeah zxwut is more correct (sorry zxwut). Torquy, and thirsty, but i bet it runs quite well!

 

Not a comment on the engine, but on the drive. Most likely it has the OMC King Cobra outdrive on it. Best advice I can give on that is to buy a OMC manual, not the aftermarket one (like Seloc), but a honest to goodness OMC factory manual... OMC Cobras at times get a bad rep for gear issues, but, when adjusted properly, they are stronger than comparable merc's of the same era. The biggest thing seems to be finding someone who can adjust the shift linkage properly. My 20' Sunbird has a 302, that I added a cam, intake and 4bbl marine holley to, with a thru the transom exhaust with stainless dumps, and I have had no issues with the regular (not King) Cobra handling it.

1990 OMC KING COBRA STERNDRIVE SERVICE MANUAL PWS MODEL - eBay (item 230524309139 end time Jan-07-11 13:14:59 PST)

EDIT: My bad, I see you mention it has a Merc based 460 in it... can't help there, altho I still suggest finding a factory service manual. The Seloc manuals leave alot to be desired imo

 

Thanks for that. Yeah, it is a King Cobra and not a Merc. Thanks for the heads up on the OMC manual.

Yeah this is a cruiser but it still has that 460 in it. The stock 460 will turn 330 horses. I went and looked on Edelbrock yesterday and I can get heads and a carb for this motor that will give it up to 600 hp. Now I ask; what would be so bad about a 25' Donzi cruiser that is capable of 70+mph on the water? I am planning on just enjoying the boat for this coming spring but next fall I am gonna pull and rebuild that 460 and get some serious hp out of it.

 

OK... since it is a King Cobra, let me throw some things out your way to keep in mind.

Depending on the prop, that boat should be capable of running close to 70 as it is now. Some mild changes are all you really need

1. intake,
2. better carb,(stock is a 600cfm Holley)
3. change the manifolds out (I would suggest this anyways if they are original)
4. Thru the transom exhaust if it doesn't already have it
5. a mild cam

Thats really all you need to do to wake it up. The 302 in my 20' with the same mods will hit 60+ with no issues at all.

Anything more than that and get ready to start spending SERIOUS money, as you will have to do things like upgrade the outdrive to handle the power, convert over to freshwater cooling, reinforce the hull and transom for the power, etc...

Also, when I say mild cam, I mean MILD cam. Unless you convert to dry exhaust, anything over about 230 duration you run the risk of reversion pulling water back INTO the motor at idle and lower speeds... not good!!

 

Thanks L.Ward

Better intake? Are you talking about the intake manifold?

A 750 cfm edelbrock marine carb was already on my list. Jegs has remans for around $300

Change the manifolds. Intake and exhaust?

I am pretty sure it already has through transom exhaust.

Sorry for my newbiness but what is a "mild cam" I have looked at some marine cams on jegs and I have read a little bit about marine cams. What I have read is that since marine engines don't have "gears" in that you don't go 1-2-3-4-5 then what you have to get is a "broad powerband cam" or a cam that creates consistant power across the RPM band. Is that what you are talking about?

thanks again for your help in understanding this.

an image of the engine in the bay

http://1.photos.ebizautos.com/6085/6...6471114_45.jpg

 

In your searches for info on your boat and outdrive, beware!: OMC Cobra bashing is rampant on most the boating forums out there. I have no experience on the "King" Cobra, but my '93 5.0 EFI OMC Cobra has been problem free it's entire life with regular maintenance only. My buddies 89 Cobra has also had no problems. Good luck, looks fun and fast!

 

• Intake manifold, something along the lines of a Weiand Stealth
• Carb, skip the edelbrock, and look at the 0-9015-1 Holley 750 Vac secondary
• Exhaust, there is not alot available for the 460. GLM doesn't make anything, and NOS is nonexistent. Hardin Marine, in Port Orange, Fla. does make some manifolds and systems. Your best bet is to call them at 1-877-900-7278
• Exhaust tips, once again Hardin Marine.
• Cam, a Comp 34-232-4 (218/224dur 514/524 lift @ .050) is going to sing all the way to 5000 rpm, and starts pulling right around 1000rpm

Also, the guys at Hardin are good to deal with on tech questions. Even tho they are more geared towards the offshore boats, they took the time to answer questions and provide advice for my little 20' 302 powered sunbird.

Two last things to keep in mind on a boat.

1. The two happiest days in a boat owners life... the day he buys the boat, and the day he sells the boat.
2. A boat is a big hole in the water you throw money in!

 

Good deal... sounds like you have a mechanic that knows how, or you took the time to adjust it right during maintenance. The biggest thing that kills OMC's is guys (and many "marine" mechanics) dont take the time to learn how to adjust the shift properly. Then they eat the gears out of the things. If adjusted properly, they will handle more power than a Merc of the same year and be trouble free to boot. Personally, I will take an OMC over a Merc.

 

OK, thanks fellas. I have been looking around on the internet and it seems that there are several forums dedicated to OMC sterndrives. These guys seem to be as fanatic about their drives as the old nuts over on the IDI forum... Looks like a good resource.

 

I heard that BOAT actually stands for "Break Out Another Thousand"

Anyway, I have wanted my own boat since I was a kid. I have been studying about them seriously for around 5 years now. I figure it is time to go ahead and pull the trigger.

 

Correct on the first part! I have too many projects and no time to be wrenching on the boat. My boat goes to the dealer it was bought from every year for maintenance and winterizing since it was new. You would never know it was a '93. It also matches my F250





Sorry, hijack over.

 

This is a good site for OMC adjustment info

OMC Cobra Sterndrive Tech Info

 

well my step bro had a cuddy cabin 24' sea ray.... it had a 350 in it...

this is no lie it costed $75 in fuel a day lol and that was 3 years ago