Replacing 5.0 with a 4.3 vortec, or 5.7

[TinManMike]

New to the forum and have a question as far as installing a new motor in a winter project. I purchased a 1990 Wellcraft 196 Eclipse with a froze-up 5.0, 2-bbl. I knew this going in, no question. I have the opportunity to pick-up a 4.3 vortec to put in the boat at a substantial savings from purchasing a new 5.0 long block. The info I have been able to obtain does not list a 5.7 as an option for this particular model, only the 5.0, 4.3 or the 3.0, I believe.

Obviously insurance concerns come into play if I install the 5.7 as the boat is not rated for Hp above 200, but will the 4.3 Vortec motor be a better choice than the 5.0, 2 bbl. Playing with the options and need to pull the trigger soon if the 4.3 is a viable option for this boat.

Not looking for a speed boat, pulling some teenagers on wakeboards on skis and family outings on the lake. I have a 26' offshore fishing boat with twin 250's for fishing. Just don't want to be disappointed with a dramatic amount of lack of power with the 4.3 Vortec.

Thanks for any replies,

Engine Serial # D382836
Outdrive Serial # 00365484 Alpha I

Mike

 

[chris.j.marshall]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

The 5.0 was frozen when you got it? You'd notice some difference if you were used to the V-8, but the 4.3 will tow skiers with ease. Is the 4.3 EFI?

 

[greg82255]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

With a 20' boat, you won't need anything more than a 4.3.. it should have no trouble pulling skiers.

If it's the alpha drive you are concerned about, it will certainly handle the power of a 5.7 (~260 hp). It can even take a 5.7 vortec (~300 hp), but that's about its limit (well, its rated limit at least). You could get a 5.7 long block for about $1700 shipped - it appears that the prices have gone up since I last checked.

If you are running a thru-hull exhaust, then keep the V8.

 

[John_S]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

My vote would be a 5.7L, either standard head or vortec head 4brl. Pulling out a skier or trying to stay on the edge of planning for wakeboarding, you will be happier with a 5.7L.

I/O hull ratings are not like outboards. The rating will be matched to the motor it came with. A 19' boat will not be overpowered with a 5.7. The 5.7 will weigh the same as 5.0 and keep current attitude in water.

If the 4.3L is not a marine package, than ignition, carb, accesory brackets, and other parts can add up. It will require exhaust manifolds, where if the 5.0l are not freeze cracked, may still be good.

 

[90stingray]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

OP welcome to iboats! I would think that the 5.7 with your 5.0's accessories would be the best option pending the gear ratio... Someone needs to decode that serial number. Didn't some 5.0's have the 1.84 ratio where all 5.7's have 1.50? Or if you have the 1.50 it may not work well with a V6 that needs a 1.84. Just a thought...

 

[Tail_Gunner]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Pick yourself up a 5.0..it will save money on parts..The 196 should do 50 plus and your insurable with kids. Unless the 4.3 is dirt cheap that is. There is little difference between a 4.3 vortec and a 5.0 in perfromance..Non mpi that is. Is this a boat fuel injected?

 

[TinManMike]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Pick yourself up a 5.0..it will save money on parts..The 196 should do 50 plus and your insurable with kids. Unless the 4.3 is dirt cheap that is. There is little difference between a 4.3 vortec and a 5.0 in perfromance..Non mpi that is. Is this a boat fuel injected?

Thanks for the replies guys.

The boat is not fuel injected. The price on the 4.3 is right, and it is a marine set-up. I was researching this forum and it seemed that many people were recommending switching from the 5.0 to 5.7. Is the gear ration found on the outdrive itself, or do you have to search by the serial #?

Also, I f I did decide to go with the 4.3, would the motor mounts work without major modifications?

Thanks again for all replies.
Mike

 

[Fishermark]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Also, I f I did decide to go with the 4.3, would the motor mounts work without major modifications?

Depends upon your definition of "major." They certainly need to be moved. How "major" that becomes depends upon your boat and stringers. Shouldn't be too difficult, but you would have to determine that yourself. By far the easiest would simply be to buy a new long block as Greg mentioned. I personally would go with the 5.7. Then simply transfer all your externals and you're done!

 

[90stingray]

Drive ratio is on LH side usually fwd of the s/n.

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[Bondo]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Thanks for the replies guys.

The boat is not fuel injected. The price on the 4.3 is right, and it is a marine set-up. I was researching this forum and it seemed that many people were recommending switching from the 5.0 to 5.7. Is the gear ration found on the outdrive itself, or do you have to search by the serial #?

Also, I f I did decide to go with the 4.3, would the motor mounts work without major modifications?

Thanks again for all replies.
Mike

Ayuh,.... The odds are, you can go with the 350, as usually the 5.0l uses the same drive ratio...

Go with the 4.3l, 'n you'll need a Different drive ratio....

 

[John_S]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

If you want the 4.3, make sure it is a vortec head, not just "vortec" on the valve cover. You want everything from flywheel forward, all bracketry and accessories, exhaust manifolds, and elbows.

IMO: drive ratios can be off by the next closest ratio, and it won't be a major issue. You can compensate with prop pitch. If your drive is worn, an sei replacement with whatever ratio you need is an option.

But, repeat after me, 5.7, 5.7, 5.7, 5.7.....

 

[ChampionShip]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

I've seen plenty of 30' class late 80's early 90's go boats with alpha drive 454's even some with plenty of mods and turning pretty big wheels.......I vote for the 5.7 vortec.

 

[SuperNova]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Thanks for the replies guys.

The boat is not fuel injected. The price on the 4.3 is right, and it is a marine set-up. I was researching this forum and it seemed that many people were recommending switching from the 5.0 to 5.7. Is the gear ration found on the outdrive itself, or do you have to search by the serial #?

Also, I f I did decide to go with the 4.3, would the motor mounts work without major modifications?

Thanks again for all replies.
Mike

I had a 20 -foot boat with a 4.3 and it's time to plane was very disappointing and only got worse with load. If you put six normal sized adults in it would really struggle, but it eventually would plane off. The outdrive had 1.84:1 gears in it. I eventually converted the boat to a 5.7. I would recommend staying with the v-8. It isn't about horsepower; it's about torque...and the v-8's have more.

As far as the motor mounts got, the 4.3 v6 is identical a small-block chevy v-8 with the two cylinders missing so it's shorter (length not height). ALL of the accessories and brackets from your 5.0 should bolt to it and work. The motor mounts will also bolt to it without any modifications and will line up on your stringers about two inches farther back than the holes for the 5.0. When I put the v-8 in mine I used everything from the 4.3, including the flywheel and bell-housing. I used the same engine harness, the same cable mounts, the same ignition box, etc. The only thing I had to buy was the exhaust manifolds for the v-8. Still running just fine.....

 

[TinManMike]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Looks like I'll stay with a v-8. The 5.7 long block is only a couple hundred dollars more than the 5.0 long block.

Thanks again for all of the replies and I'll post some pics when the re-build gets going.

 

[dan t.]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Most 305 2bbls came with a 1.65 ratio leg, the 350 should have a 1.5. That being said I swapped from a 305 t0 a pepped up 350 magnum and kept the 1.65 leg. I ended up going up 3 pitches in the prop,( 16 to 19) so far so good.

 

[TinManMike]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

I checked today and the outdrive has the 1.65. Is the 1.5 necessary to install the 5.7? I know Dan T. said his is working fine, but is this a concern? No magnum motor, just standard 5.7.

 

[SuperNova]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

I checked today and the outdrive has the 1.65. Is the 1.5 necessary to install the 5.7? I know Dan T. said his is working fine, but is this a concern? No magnum motor, just standard 5.7.

I ran mine with the 1.84 gears from the 4.3 for 3 seasons and never had an issue. One of the advantages to switching to 1.5's is there is a heavy-duty version of the 1.5's that were used with the big-block installations. Installing these gears go a long way towards strengthening the outdrive upper. The 1.65's should work fine, but you may find a pitch increase necessary to avoid over-revving the engine at W.O.T. The boat will definitely get out of the hole quicker! Oh, I almost forgot, the mechanical advantage that the 1.65's give the engine may cause you to cavitate the prop a little easier on acceleration, so you may want to go to a 4-blade for extra bite, but I would try it first.

 

[90stingray]

I checked today and the outdrive has the 1.65. Is the 1.5 necessary to install the 5.7? I know Dan T. said his is working fine, but is this a concern? No magnum motor, just standard 5.7.

Sorry, I said 1.84 earlier... I meant 1.65.... I knew the 305's had different gearing than the 350's I think you are close enough with the gearset you have and most likely wont need to do anything... maybe a prop change to get her dialed in.

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[joewithaboat]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

I have a 19 foot open bow with a 4.3 non vortec. Its propped right, has trim tabs, it pulls a 250lb skier or two tubes with ease and runs 50 mph to boot. Before trim tabs it was terribly long to plane. The 4.3 does amazingly well on fuel consumption.
All that said id still take a 350 any-day, would not trade it for a 305 though.
If that 4.3 is that cheap you could buy it, flip it, and use the proceeds toward your 5.7.
Good luck!

 

[TinManMike]

Re: Replacing 5.0 with a 4.3 vortec, or 5.7

Well, I went with the majority of the opinions and purchased a 5.7 yesterday. I'll be stabbing her in the boat when the floor and stringer repairs are complete. Getting stoked to finish the floor and get this new motor installed!

Thanks for the input guys!