1988 Twin 460 and King Cobra outdrive for new home

[JonBrown]

I recently bought the boat I always wanted. The 261 Libby. And the 460 twin engines puuurrr like a kitten. The drives are super clean . Both rebuilt 36 hrs ago/use. (engine and drives)
Here is my problem. I have 2 - 6.0 corvette EFI engines in my floor and I think as for going out in the gulf they may suit my needs better. So I may be willing to sale my 460 king out drives and engine whole and as complete. All of it really runs great. I will even throw in the factory Morse sports controls(4 Stick) if needed. What are these things worth? I see a few listed and they are expensive but I never see a complete set of counter drive and etc. I will add the exhaust looks poor. I would say I will not drive with them again after seeing them . Probably original.
I think if I could find a set of Volvo SX or compatible I may do a little better on fuel? Or maybe it will be the same ? I don't really know. So I guess I should ask if the 6.0 gets good or same mileage as the 460? The power and torque are the same at stock form. Anyway there is my want/wish list .. If you have any input then I want to hear it. Just a brain fart. We started to remove the floor and interior of course to freshen her up. So if I am to make these changes I should do it now. Once the floor is down then they stay. Oh yeah, everyone knows about the OMC king trouble and the ford power plant. But let me tell you. That throttle is a whole lot of fun! Oh my ... So I don't believe all I hear about the OMC King story. Tell me what you think, what the value may be? Or if you have have the OMC or Libby, just add your story..

Thanks Jon

 

[Scott Danforth]

the cam's in the 'vette motors are wrong for marine use. close lobe centers and large overlap. perfect way to suck water (reversion). There are plenty of 6.0 marine motors, so you could swap cams, reprogram and be off and running. the aluminum 6.0 LS motors are about 250# lighter than the 460's (each). that is significant weight reduction.

If it was me, I would go for it, drop on a Magnacharger with the correct marine cam for a bunch more power

 

[JonBrown]

I was thinking the same thing. And yes the cams are way off. But wouldn't it be kool to lift the hatch and see the vettes under there?
I think the only way I will do it is for the fuel burn. If that would improve..
Jon

 

[Scott Danforth]

unless you move to diesels, spark ignited engines burn about 0.35 #/HP-Hr of fuel. so if you have the same HP requirements for the same length of time, you burn the same fuel. the 500# savings will help.

what would be cool to see would be twin 1650's

 

[JonBrown]

I am a Yacht diesel mechanic. I like them but this vessel is about sound and booze cruising. My Chris Craft runs 8V71 , a engine I hate and love.
I want to keep this one gasoline. This is my "little boat"

 

[Scott Danforth]

I'm a Cummins guy at heart. I understand the love /hate relationship with the slobbering jimmy

 

[JonBrown]

I like the Cummins in a boat. Not so sure about the truck engine though. Of course the diesel you have is the one you like after all. I like mine because they are paid for. They are the best. lol

 

[JonBrown]

After doing the math and a few 6.0 or 6.2 owners advice and compare of 10 knots to WOT I guess the difference is pretty small. I will just EFI the 460's and keep them. Update what I can and build the new stainless exhaust as planned. And baby those out-drives for 10 more yrs. Guess my SHELL card needs a new limit..lol
Ill spend some cash on a good sound system and just play the engine sound at idle.. I found my top hull speed with 340 hp is about 50 ish.. I never drive 50 . So im good with the old Fords.

 

[Scott Danforth]

EFI doesnt buy you anything in a boat other than the need not to set a choke for startup and slight auto-AFR adjustment advantages if you switch elevations often. the new closed systems with cats do improve throttle response throughout the range, however an open loop speed density or MAF system doesnt add economy, or power. adding to a motor that currently runs is not financially worth it. then again, the whole idea of a boat is not financially feasible. I personally would pocket the money you are going to spend on EFI and put it into fuel.

 

[JonBrown]

I sale the EFI kits and they are cheap. It keeps the old 460 from burning pistons in a 3 hour run. If or when the old Holly's tend to screw up. And it may , not guaranteed but may save me a gallon or two needed to get home. The EFI also lets me put a choppy cam in and it doesn't die when you engage gear.
So the plus is easy start, choppy cam. And your right not feasible. But doable.. That is the boat world. Plus I can market it from my boat.
Jon

 

[Scott Danforth]

are your EFI kits SAE J1179 compliant? I have never found a Cheap EFI kit that is SAE J1179 compliant (Marine), especially one at 750cfm or larger (what is needed to feed the 460's)

Never had a maintained holley carb ever screw up, however that is my experience. I have added the back-fire prevention check (125-500) to any old holley carb I have ever come across to prevent blowing the power valve from a sneeze, however the carbs for the last 20 some years come with them.

Choppy cams are a no no in boats with wet exhaust on I/O's, unless you go straight out the transom with a dry exhaust. generally anything over 270 degrees of duration is prone to reversion. has nothing to do with the induction system. dying when going into gear is the shift interrupt switch needing adjustment.

 

[Bondo]

The EFI also lets me put a choppy cam in

Ayuh,.... Welcome Aboard Jon,.... I can't believe my Hero Rick ain't been into this thread yet,....

He's got a single motor copy of this boat,..... I think I'll pop 'im a pm, linkin' yer thread,....

I agree with Scott on the cam though,....
Choppy idle, Ain't a boat cam,...... idle to 5000 rpm is the cam cut for a boat,.....

A truck/ RV/ Grunt kinda cam,....

Good luck with the Ford/ King Cobra trip, it's a voyage I wouldn't take, myself,......

 

[HT32BSX115]

I sale the EFI kits and they are cheap. It keeps the old 460 from burning pistons in a 3 hour run. If or when the old Holly's tend to screw up.

Howdy,


Don't know why your 460 would "burn" a piston in any length run. My 87 211 Liberator went almost 20 years with the original carburetor without burning anything! Only thing that went wrong with it was the a few flat camshaft lobes and leaky riser gaskets (on NLA exhaust manifolds)

About 10 years ago (Bill, has it been that long?) I removed my 1987 OMG 460 King Kobra and replaced it with a 1997 454 Bravo III. The single engine Libs are real dogs out of the hole (I might assume that the 261 is even slower on holeshot)

With the 454 bravo III, the holeshot is now like a ski-boat.....In fact, I think I can beat most ski-boats out of the hole! With the 460, single prop cobra, and 20p stainless, once it was finally on plane, it would do about 60mph at 5000 rpm and was a real DOG out of the hole................

Now it does 57mph at 4600 RPM with 26p props. I put a fuel flow meter on it and at 3000 RPM & 30mph, It burns 10 gallons/hr........and now just ROCKETS out of the hole.

I was also able to sell all the OMC junk, piece by piece over about a 3 year period for total of about $3500. Last week I sold the 2 stainless steel props I had laying around for about $160 on ebay............ so now I'm up to $3660! woohoo!

You're really going to be wasting your time, money and ensuring that the boat stays pretty much worthless by keeping the OMC power.

If I had a 261, (and I seriously considered getting one!) I would part out all the OMC "stuff" and install aluminum block carbureted and closed cooled 383's with aluminum exhaust + Bravo III's

My 2nd choice would be "off the shelf" EFI 383's(or whatever Mercury calls them) , 3rd choice: Merc 496's and my 4th choice would be the same engine I have now. Twin 330 (crank) hp carbureted 7.4L and Bravo III's


The 261 is a cool classic semi--go-fast boat! as long as it's "sound" (no rot in the floor or transom) , repowering with modern supportable engines and drives will make it run well for another 20 years! And it'll be worth "something".....


Good luck,

Rick

 

[JonBrown]

It wouldnt normally burn a piston. Yet I have because the carb loaded up and timing issue. . It was a lack of maintenance on my part. I am only fuel injecting it with a bolt on like a 4 barrel because we sell them at my shop . It does run a little more on the perfect side. But mostly because it is free. I run the bolt on EFI on my airboat and it is awesome. 40 degrees just turn the key and she lights off. And as far as the hole shot? Well mine is a twin 460. It doesnt do bad. But I am just trying to take care of the drives. After these go bad it is Bravo or? Who knows. And a repower. I have a few yanmar diesels but that would kill the Liberator spirit.

 

[JonBrown]

Bondo, ( like the name)
I just want a little chop. This is my only gas boat . It is fun to go play with the kids in the water . They have the newer 502 and I just slowly hole shot and walk away.
I have kept mine original in form but there are a few updates for this year. Synthetic teak floors. New paint. I do need a few things and Rick may be able to lead me to the correct items? Like one of my wing glass is broken and the previous owner lost the hinge piece. Just little things..

 

[JonBrown]

And Scott... The EFI takes care of the dying in gear. It starts in 40 degrees like a champ. It starts next season. It starts everytime. It also reduces 70% of the fumes in your bilge. I understand you guys like carbs.. I get it. But the EFI is awesome! And if you PM me I can discuss the cost. It is compliant and it works! Trust me it is cheap and youll love it. I have installed it on chris craft 429,460,454,350,305 and the customers love it! My kit is good for 400 HP. Then it gets expensive.
Also I have 2 of the 4 stainless exhausts made for the Libby. Her name is "Bad Girlfriend" lol

 

[Scott Danforth]

taylor made sells the parts for the wing windows

 

[JonBrown]

Sott you are my hero! Buddy I have been looking everywhere for that!

 

[JonBrown]

The few things on this boat that bug me is the windshield doesnt have the proper trim. Someone kind of botched it up. It will come off . The wing glass of course . Someone glued the port closed. I removed the windshield and frame because it seems loose and flexing. The Bomar hatches need a little repair. And those electric hydraulic seats.. I havent quite figured out what to do to it.