Inthechateau

Hi everyone, this is my first post here and looking to get my project in the water this summer in Maryland.

I picked up a 24ft Bayliner Trophy and trailer a few weeks ago in a really good deal. FREE with papers! Looks like engine is toast as it is locked up. I have not pulled heads yet to see exactly what is going on, but rest of the craft seems to be in fair shape. Needs a good cleaning and polish job and bottom paint. Looks like only thing missing is a depth finder.

The Trophy currently has OMC Cobra drive and a 350 SBC engine. If I cannot save this power plan I am looking to see if the 454 I have under the bench is feasible to install. I have no idea what all needs to be changed to make a match. Drive shaft, flywheel, I know the EXH manifolds are different so I am exploring the possibilities and options. Any help would be appreciated. Really looking forward to cruising the Chesapeake Bay again.


I have been away from boating for a long time and this will be my reintroduction to water craft. Plan on attending a CG class and update my safety and skill set for the sport and get back to fishing.

offshore312

Everything that I've seen with Big Block power has been mated to a King Cobra Drive. No clue on how long the standard Cobra would hold up with BB power. Some mfgr's experimented with putting Alpha drives behind BBC power in the 80's, but they didn't hold up very well under any hard use. I believe the bell housing patterns are the same SBC/BBC, so you may have a bolt up at the drive & minor fab at the engine mounts. You will still have to find a flex plate that will work with your engine / drive combo, and you'll have to source exhaust manifolds etc. for the BBC...That being said, unless you're planning to join the Bayliner Racing Team (see their page on FB) it's possible that this could work for you.

jadento

Welcome!

I do not have much technically to add for you, but my suggestion would be to stick with the small block power. There are plenty of reasonably priced ones around that you can drop in and be off! My guess is a 454 will only change the speed a handful or less MPH. Provided you are able to find an appropriate prop. The money you would put into said "laying around 454" to make it work will likely quickly surpass a decent running used 350.

Again welcome and maybe Ill see you on the bay this summer!

dereknkathy

it is a bayliner trophy. it is made to do about 45 tops. it will be cheaper and easier to purchase a 350 than to convert an already-paid-for 454.

dereknkathy

the cobra is a direct copy of the alpha. gears the same size. i have heard you can interchange gearsets between the 2. if you are gonna drive the boat it'll hold up. if you are trying to build a sleeper (the hull is too slow if you put 1000 hp in it with an arneson) you will break it quik. if you insist on trying the swap all you REALLY must have are exhausts and the bracket that mounts alt-power steering. i did this once with an early formula and even re bent the steel fuel line to fit the 454. and i think i have a bracket i can let go...i bought it for the formula swap.

Inthechateau

Thanks for the input everybody. After doing some more research we will continue to search for a reasonably priced 350. This is a tight budget project just to reintroduce into water sports. Retiring in a couple years and don't want to go into debt to put a boat in the water. Looked into the conversion after a few of your comments and WOWEEE, those 454 parts are pricy. Want to spend money on tackle bait, and beer........... This 454 I have was from an unpaid customer job. Might try to sell and pick up the engine I need for this one.

Budman II

iTrader: (1)

That's your best plan. Plenty of decent used 350's laying around, and even new crate motors are relatively cheap.

CC230

For example, in the swap shop and in MD also,,,http://www.offshoreonly.com/forums/s...ser-350-a.html

I would stick with a small block for what you want to do.

Jonesyfxr

iTrader: (1)

Grab a vortec 350 from a bone yard, rebuild it then go to town!!

mrv8outboard

Just to give you some more info, They make a conversion kit that will use your OMC Cobra transom assembly and a Mercury Alpha drive. This way you would not have to redo the transom if in the future you needed a drive replacement and did not what the Cobra.