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View Full Version : Converting to Bravo I from OMC KingCobra



Franko_1000
06-30-2003, 10:48 AM
I have a Z-25 with a 460 and an OMC KingCobra. 2 years ago I had to replace the outdrive because of gears. Now I get to replace it again. I don't really want to put an OMC back on and I don't have the money to buy a new motor/outdrive and all of the conversions at once. Is there a way to connect a Bravo I to a Ford 460? Do I really have to cut the transom and reglass or is there a plate or conversion kit of some sort available? I have had no luck on the Mercruiser boards so I thought I would try here. Thanks for any help you may have.
Chris

Forrest
06-30-2003, 10:57 AM
Why not convert to a Volvo SX (http://www.donzi.net/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=4;t=000400)?

Franko_1000
06-30-2003, 11:33 AM
Would that be an easier conversion? Cheaper or more $? More reliable/efficient? I had not really thought of Volvo. I have 3 other boats with Alpha drives and have been very happy with the reliability. I do have a 20 Glastron with a Volvo drive but have only had it for 1 month so I don't know if I like it or not yet. It does shift nice but that is about all I know.

Thanks,
Chris

Ranman
06-30-2003, 12:50 PM
I'm pretty sure that the King Cobra and Bravo One transom cutouts and hole locations are the same. This would make for a relativly easy swap. Is the Volvo SX cutout the same too? I wonder what's the matter with the Kung Cobra? They are supposed to be pretty bulletproof and should handle basicly the same power as a Bravo. I'm just wondering if your problem is really with the drive or if you'll likely encounter the same problem with a Bravo? Merc did offer some Ford power packages here and there a while back. I would think all you would need to mate a Ford engine with a Bravo would be a coupler and bellhousing for the Ford (if they were made).

Franko_1000
06-30-2003, 01:25 PM
The first drive replacement (2 years ago) was diagnosed as a mis-adjusted/worn intermediate cable that caused the gears to not fully engage. I had purchased the boat used and he gave me the receipts that showed the cable being replaced prior to my purchase but I guess it may not have been properly adjusted. This time it is my fault. After "helping" my mechanic change the fluid I may have over tightened the lower screw and torn the o-ring. After a week of sitting in the driveway losing fluid, I hit the lake and made it 5 miles before loosing my upper gears. I guess these outdrives do like to have fluid in them. My main reason for liking the Bravo drive is that I have not had any mishaps with the ones that I do have. They also have the nice resevoir right next to the engine oil that I can check an monitor without taking the boat out of the water. I just spoke with someone from Performancemarine.net and they basically told me that a flywheel is going to be the only problem. Pretty much they don't exit as far as he knew. Maybe someone here knows more? I sure hope so because he quoted me $18,000 for a 496 with Bravo I. Ouch! I didn't pay much more than that for the boat. Also I have heard that the Bravo I drives are more effecient than OMC and parts are easier to find.

Forrest
06-30-2003, 02:12 PM
The Volvo SX uses the industry standard (Mercruiser) transom cut out as well. Basically the SX uses King Cobra gear housings, but uses the Volvo-Penta shifting mechanism, gears, shafts, and other internals, and is built in the USA.

MOP
06-30-2003, 05:19 PM
Check parts 4 sale there is or was an XS there, though a Cobra is really hard to beat and your problems sound as if they were induced not inherent. You rarely find them in the shop, Bravo, Cobra and SX are your best drives. They all need proper maintenance.

Franko_1000
06-30-2003, 11:04 PM
You are right the two issues were induced. My logic is that I have 3 boats with alpha drives that have never had a problem, one with an SX drive that I have only had for a month so I don't know about its reliabilty, and one OMC that has already been replaced once and is now going to be replaced again. I also want more power than the 460 is producing. To get that I think I will have to go to a Chevy eventually. I just don't have $$$$ to do the project all at the same time.

MOP
06-30-2003, 11:29 PM
Hmmmm 534 might fit :D But Chevy is much better parts wise.

Franko_1000
07-01-2003, 09:27 AM
So Forrest, the drive you have up for sale. You say price reduced in your post yesterday. What have you reduced it to. Are there different SX models for different hp? My new Glastron has the SX drive on it but only a 5.7L. Wouldn't a 454, 496, or a 502 destroy it? I have tried to find a site that explains the different models by Volvo-Penta but have not found anywhere that lists all options/applications etc. I know you say it can handle up to 500hp but I can't find anywhere on the Volvopenta.com site to tell me that.

Thanks,
Chris

RickR
07-01-2003, 09:38 AM
Frank
What year is your King Cobra?
Does the drive have a flat top or a hump?

The King Cobra was changed in the 89-90 model year.

Forrest
07-01-2003, 10:42 AM
No, a big block will not distroy a Volvo SX. Volvo SX packages have included 502 cubic-inch big blocks. Their current big-block 8.1 L (496) uses the SX-DP drive which is the duo-prop version of the SX. This package is rated at 420 HP @ 5000 RPM. I really don't know its top power rating, but should be about the same as a later model Bravo, which is in the 500-550 HP range. Make no mistake, there is a substantial difference in power handling capacity and build quality between a Volvo SX and an Alpha.

MOP
07-01-2003, 01:16 PM
I go with Forrest on the quality of the Volvos every one who has one will attest to the durability and the quality of the guts and the aluminum. They are one tough bugger, in school they showed us a film of one hitting a submerged piling at over 50 they hit it atleast 5-6 times with no damage what so ever. And very rarely do you see one rotted from corrosion. Question how many 250 or 270's with around 400Hp are out there? Those were lighter drives, many are 25-30 years old still ticking.

BUIZILLA
07-01-2003, 01:54 PM
Forrest speaks the truth.

J

Franko_1000
07-01-2003, 04:29 PM
I may be somewhat sold on Volvo but I still have the problem of finding a flywheel to connect it to a Ford. Any ideas? It is an 89 KingCobra with the flat top i guess. Just like this one King Cobra on Ebay (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=26455&item=2421127063)

Forrest
07-02-2003, 09:06 AM
Wouldn't your Ford coupler, bellhousing, and inside transom plate from the King Cobra work? The input shaft size and spline should be the same as the Volvo SX.

RickR
07-02-2003, 03:47 PM
Frank
I believe the early model King Cobra like you have has a dog clutch like a Alpha.
You would be much happier with a drive that has a cone clutch like the one Forrest has for sale (Volvo, late model King Cobra and Bravo).
The SX is similar to the late model King Cobra which is a great unit. I preferred it over the Bravo I have now.