New Engine Time

[edgewater1]

In will be needing to replace my engine winter project, the boat is in maine, i would been interested in recommendations about engine replacement, i would like to replace with a 351, or a 350, i will need a to buy a new or rebuilt transmission. It is nothing that will happen instantly, but it will need to be done this winter.
The only 100%'s are:
-Carborated
-To fit in a 1991 sunsport
-Run when needed, "when i use the boat, EVERY-TIME"
- Older "non" electronic ignition

(Side note-Anyone ever heard of someone putting a 383 Stoker in a boat?)

I would also like to do this as cost effectively, i know its a boat but if some knows how to get it for a better price, it never hurts.


EDGE

[DKJBama92Mariah]

There is a used 454 and trans listed in the classifieds. https://forum.supraboats.com/showthread.php?t=7697

[beast 496]

Check out the 454 package, could be a great upgrade, Make sure the engine is winterized first though. It is getting cold this week. Al

[rludtke]

My first thoughts are that replacing the 351 with another would be cheapest, as you already have most, if not all of the needed parts. Despite the fact that I prefer GM, switching to a 350 is a only a lateral move power-wise that would only add more cost.

The big block Chevy and transmission deal changes the equation. Yes none of your parts wll fit, but the extra tourque and power may make it worth while. This is a personal call, but in my mind, go for the cubic inches. You can never have to much power! :)

[sybrmike]

Cheapest/fastest by far is just another 351. The big kicker in engine swaps is all the accessories. Water pump, mounts, brackets, manifolds, etc. really add up quick so if you're staying small block - I'd stick with the Ford. Yeah, a 383 would be nice (displacement = torque = good), but a SBF can be stroked too.

OTOH - if that BBC comes complete with all accessories & the price is right...

[87SunSportMikeyD]

I just got done replacing my 351, If you find a newly rebuilt shrinkwrapped longblock 351W (left or right hand rotation???) motor on craigslist and find a private mechanic you can save about 50%. Cost me 950 for engine, 1700 for other parts and labor (50$/hr). A big dealer would be about double that. Note that there are 'ranges' of acceptable 351s for your model year. For example, I was told the engine I chose would be compatible with 86-89 SunSports and mine is an 87.

More details on my P&J thread or PM me. It sucked but it had to be done, bad compression on 6 cylinders. She rips now!!! Dang fall and winter grrrrr

[edgewater1]

I'm definitely sticking witha small block, so i guess replacing the 351 was the overall agreement, now, Is fuel injection worth it???

[beast 496]

GT40 Ford 351 from PCM would be great. Might be hard to locate though. Many Nautiques had these installed. The EFI runs great, would be an easy install also.
Since you are not interested in the 454 I might look into it. Al

[87SunSportMikeyD]

...Really??? Is a GT40 feasible? I'm no engine pro, but that has been the most rock-solid and best performing engine I have drove yet. If u could have an EFI gt40 that would SOOOO rock....

[beast 496]

I have several customers with the GT40 Ford 351. I would really like to have one also for an old Mustang we have. Al

[87SunSportMikeyD]

I guess I was wondering if this is something that can bolted in to your boat without having to make too many expensive modifications.

[edgewater1]

anyone ever heard of someone putting a 496 in a supra, and a follow up, It's going to be carbs, Rochester, Edlebrock, holley??

[beast 496]

I have a 496 in my Supra Beast. The Current 8.1lt or 496 is based on the LS platform, These are only MPI, no carb is available for this type of engine. In fact, no intake manifold other than the MPI style. On the old Mark V platform engines, you could stroke out a 454 and turn it into a 496 but it would not be very reliable in a marine version. Here is a photo of a 496 Ho 425 hp
http://i957.photobucket.com/albums/ae55/alswagg/Supra%20Beast/SupraBeast003.jpg

[jet]

Wow!!!!!!!!!!!!!!!!!!!!!

[cadunkle]

Need to know a few things. What are your goals? Are you satisfied with the way your current 351w performs or do you want more power? Any idea on HP desired? What RPM/MPH range do you ride in? Wakeboard/slalom/surf? And of course, need to know the budget too.

An engine conversion will be expensive, so if you cna do waht you want in a SBF package, do it. What is wrong with the current engine? Depending on that and your goals, we could be talking about anything from a $500 freshening up to a $2500 performance build.

Also note you can stroke a 351w to 427. I wouldn't recommend it in a boat (high load and RPM, constantly) since all 427w pistons will have the pin in the oil ring. They will all burn oil and smoke after a relatively short time (about 20k-30k miles in a car, for comparison). Many 393w stroker pistons do not have hte pin in the oil ring and will give desireable wear characteristics. This is assuming more cubix inches are necessary. Basically need to know your goals first.

personally I'd avoid fuel injection. I consider it unreliable and won't even use a fuel injected vehicle as a daily driver. I certainly wouldn't want to be on the wate rin a fuel injected boat all the time. Eventually it won't start due to some sensor or other trivial thing failing, where a carbed engine would get you back to the dock. To each his own, but in my book simplicity=reliability=beauty.

[edgewater1]

"Cadunkle," I know i want a 350 i have pretty much decided to do the conversion, i'm okay with getting 220-260HP some where in that range, my budget is somewhere between 3-5k, give or take a few hundred, but it must be done right.

Now, the Knowns:
Its going to be carbs, it will be "running"

A guy has offered me his 350 out of his chevelle, it has about 300 miles on it, its a performance engine, hes a mechanic by trade and willing to put the engine in for cost.

To "make it suitable for a boat" will i need to replace the cam shaft with a marine cam shaft? or is it the simples; wiring, plumbing, gas?

To Cadunkle, whats your daily driver?

What kind of carb to you all prefer: Holley, Rochester, or edlebrock?

[rludtke]

Holley- I am a big fan.

All of my current vehicles, with the exception of my Supra, are fuel injected. I am amazed at how little (e.g. none) maintenance I’ve had to do to these cars fuel injection systems. The Supra’s carb, on the other hand, has required much attention over the years I’ve owned it.

Chances are a new carb on the boat would have stopped the need to continually tweak with it, but at least the tweaks are simple and easy. Holley carburetors are so amazingly simple and easy to work on. If or when one of my fuel injection system stops working, I probably won't know what to do with it short of throwing parts at it to see which one sticks. You take the air filter lid off and you see wire bundles for Pete's sake!

[cadunkle]

i'll make a disclaimer that I'm a Ford man, my boat is the only thing I have with a Chevy engine. There will be no advantage to moving to a SBC platform. If the boat was a SBC already, I'd say there's no advantage to going to a SBF platform. Reason being, SBF and SBC are designed nearly identical. Similar oiling system and everything. The SBF has an advantage from better fuel distribution due to a better intake and head design, and beefier head retention but at these modest power levels it's irrelevant. Just putting it out there.

As far as BBC vs. BBF ... The Ford has many advantages and if going for serious power the BBF is hands down the way to go as far as reliability and power that I won't go into in the context of this thread. With that being said, my boat has a 454 and I'm fine with that. Makes no difference at these power levels. Aside from the occasional ribbing from friends about it being a Chevy... To which I respond, "Did you have fun on the river today riding behind my Chevy powered boat?" That usually shuts them up. :p

On budget, the 351w would likely be $2k-$3k depending on what you have and what it needs would get you in the 250-300 HP range with a good build using quality components. The Chevy route will depend a lot on trans, bellhousing, mounts, linkages, cooling system, accessories, etc. Basically all the other stuff you'll need. You'd be best to try to find a complete marine from an inboard and rebuild that, which would save money over sourcing all the marine parts and accessories separately.

I can't make specific recommendations on components and engine build for a SBC as I have not done any performance SBC builds. 220-260 HP is pretty much a stock-ish build for any 350 or 351w. It won't take much to get a reliable 260 HP from either engine.

If you do run your friends 350, basically you're looking at brass freeze plugs, marine water pump and timing cover (if applicable for your front accessories, the marine parts sit tighter to the block), marine carb and fuel pump, marine distributor/ignition. Technically you "should" run marine head gaskets. If they run in fresh water I don't worry about marine gaskets, but if they will be regularly used in salt I will use marine head gaskets. The issue is rust and corrosion depending on the type of gasket.

As for a cam, that depends on what cam he has in there. Anything more than about 262 duration will likely be more than you want. Something around 268 could work but may be a pain with a higher idle speed, choppy idle, and less power down low. Anything more than 268 duration in a 350 cubic inch package and I'd be concerned about reversion with stock risers. So basically I'd be looking around 252-262 duration, if split duration, a bit more on exhaust side can help performance a bit if running unported heads. As for cams marketed as "marine"... There's nothing explicitly marine about them, they're just generally designed to make more power in the RPM ranges boats run at. I would not limit my selection to a marine cam, but would run several cams though Desktop Dyno to see what makes best power in the RPM range I'd be riding at.

For carbs... I run Holley 4150 style carbs on all my vehicles the daily driver has a 750 DP, my car has a 750 VS, and the Saltare has an 850 DP. They're simple, reliable, easy to tune, and work well. I would recommend a 650 CFM double pumper for either a 350 or 351w. I would avoid quadrajet. They are a brilliant design and meter fuel very accurately, but are complex and time consuming to tune or troubleshoot. Edelbrock is a good carb, AFB design, but leaves power on the table compared to a Holley.

My daily driver/tow pig for the past few years is an '86 F-350 Supercab with a mild 460 (425 HP/550 ft/lbs), ZF5 trans, Np208 case, Dana 60 front, 4" lift on 35" tires. In the summer I ride my '71 CB750 when it's not raining. Both are simple and reliable, I've never been late to work due to a carbureted vehicle not running... Can't say the same about fuel injected.

[DAFF]

Trying to retrofit a land engine into marine seems to be a never ending purchase... Sure the cubic displacements and looks are the same but there is way too many differences to make this a quick and EZ. Stick to a marine engin. Any displacement, always get everything from the carb to the prop and start from there. It is much cheaper to rebuild and retrofit a complete drive line than to piece one together.

If you need a bow tie under the engine cover than the BB454 is the best choise IMO. A few tweeks like different heads and the addition of a cam will truly wake up the beast!!!

[87SunSportMikeyD]

See my P&J signature thread for details on my conversion process. Basically my mechanic took every marinized part off my old engine and put it on the new one. He installed drain holes and plugs/bolts. The cylinders had some kind of a hole in the (supposed to be there) that could not be there for marinized version so he closed those up somehow.

Did you ever get your old engine compression tested?? Chances are you were running on only partial power. Your new engine (and a power prop) should have plenty of power. For the record, though, I would love the 330hp GT40 they use in 2000-era Air Nauties

[edgewater1]

The old engine is a salt water engine with 800+ hours, you really don't want to rebuild a salt water engine, its really asking for trouble.

What about a remanufactured long block, build off what i already have and just buy what needs to be put in.

[DAFF]

Keep a watch on CL for a fresh water boat in need of some love in your region. There are many low hour boats which have structural issues which during the winter months you can buy for cheap. From the two boats combine the best of the best parts to make one. In the spring sell off the extra parts and you will be able to make some of your money back.

From there I would refresh the engine and trans and enjoy!!! There is nothing better than spare parts for you boat sitting in the garage in case of a break down.