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Transtech

vortec swap

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Transtech

My mechanic states that the motor on my 1989 skier is bad its a 5.7 he wants to sell me a 5.7 vortec claims it has 380hp has any one done that swap and what is your take on it

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Michigan boarder

You should get the specifications for the new engine:

  1. Bore
  2. Stroke
  3. Cam durations & lift

Additionally, make sure you have enough air flow in and out of the engine that will match up to the build & hp potential:

  1. Carb tuned
  2. Exhaust diameter at least 3.5" out and unobstructed
  3. ETX or stainless high flow exhaust manifolds

We did my engine a few years ago, rebuilt after an overheat/detonation.  383hp on the dyno with my stock carb, but I had to do a lot of stuff to it to get there.

 

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DWhynot
Posted (edited)
1 hour ago, Transtech said:

My mechanic states that the motor on my 1989 skier is bad its a 5.7 he wants to sell me a 5.7 vortec claims it has 380hp has any one done that swap and what is your take on it

A vortec in a skier would be a lot of fun!  What's the original motor, 260 Merc, Indmar? (and what's wrong with it?)

Edited by DWhynot

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Rednucleus

Can the  old tranny handle the increased hp? 

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oldjeep
Posted (edited)

How much is the mechanic charging for this 380 hp vortec and has he got a dyno sheet? Unless it is something custom id expect more like 300 hp with stock carb, ignition, manifolds

Edited by oldjeep

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Michigan boarder
6 minutes ago, Rednucleus said:

Can the  old tranny handle the increased hp? 

I'd say probably yes, they ran the same tranny for the Echelons with the 454 as they did with the 350 (395hp vs 265hp).  Also, I know a guy on a ski team that has a Tantrum with a 383 stroker and hits 60 or so mph, no tranny problems with his.

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powbmps
Posted (edited)
16 minutes ago, oldjeep said:

How much is the mechanic charging for this 380 hp vortec and has he got a dyno sheet? Unless it is something custom id expect more like 300 hp with stock carb, ignition, manifolds

Important questions.  When I was looking at replacing my 5.7 with a Vortec, they were all in the 300-320 range.  Big money to get 380.

Edited by powbmps

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Transtech

He states it has a cam lifters and a customer valve job he is charging me 6 grand I feel that I'm at his mercy since I live in Los Angeles and my skier is in lake havasu 

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Michigan boarder
27 minutes ago, Transtech said:

He states it has a cam lifters and a customer valve job he is charging me 6 grand I feel that I'm at his mercy since I live in Los Angeles and my skier is in lake havasu 

Your entire boat in running condition is worth a little more than that assuming it's in great shape, so I would be careful.  If he is reputable and skilled he will have detailed information and will be happy/proud to share those details.  If not, find someone else or sell it as is.  Collect $3k or so from that sale, and buy another boat with that $3k plus the $6k you are ready to spend ($9k total) and get a decent newer boat is good running condition.  No way I'd spend $6k on an engine without 100% confidence in the builder.

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Transtech

I can get a stock motor from jasper for $2500 with a 3 year warranty and the mechanic says he will charge me $1700 For labor thinking on going with the jasper engine since my boat has been in my family since new my brother order it from malibu in 1989 it was all ways in storage 

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Woodski
Posted (edited)

@Transtech:  on the engine swap question - sort of, I built up my own and went a bit farther.  380 hp does require more than just the vortec cylinder head upgrade, the heads bump power level from 285 to 310, getting to 380 requires a different camshaft.  The engine in a boat, due to the way it is used, needs much more information than simply having 380 hp, the camshaft needs to be matched to the usage, you don't want too aggressive of a cam due to the need for low engine speed performance.  As noted, all the engine specs are needed, camshaft, rocker arm ratio, intake manifold configuration, compression ratio, bore and stroke in order to determine if the engine in question is a good fit.  It also needs to have all the proper marine parts.  If you consider the Jasper route, make sure you get specs on that also, you might also look around, there are other suppliers such as Michigan Motorz that offer marine engines.

Edited by Woodski

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MadMan
Posted (edited)

I wouldn't call going with a Vortec an engine swap.  It's basically the same engine, with Chevrolet's newer, higher flowing, cylinder heads that were stock on cars/trucks/boats from the mid 90's on.  They flow more air so they will give a 20-30 horsepower bump with really no downside.   You will need a different intake manifold though if the engine doesn't come with one.

Chrysler and Ford did the same thing in the 90's.  The big 3 kept their cylinder head design on their small blocks unchanged for ~40 years, then improved them just for the last few years of production.

Edited by MadMan

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Woodski

A couple of additional notes - the Vortec cylinder head was introduced (in the pickup truck application) in 1996 so that is a reference when shopping and if you do go a Vortec cylinder head route with your replacement engine, the existing carburetor calibration will be fine, a carb does not care what is under it, it simply mixes air and fuel to the calibration (jet size etc.).  You may need to upsize it if not large enough due to increased air flow.

So, what does your mechanic say is actually wrong or broken with the existing engine?  As a purist, if you do have a motor, it is very quiet as that is an electrical device and you have one of very few electrically powered boats.  Vortec heads won't make a difference  :whistle:

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Transtech

@Woodski well besides the bad head gaskets and 2 cracked cylinder heads he claims 3 cylinders are rusted out and the  cylinder walls are pitted 

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Michigan boarder
14 hours ago, Transtech said:

I can get a stock motor from jasper for $2500 with a 3 year warranty and the mechanic says he will charge me $1700 For labor thinking on going with the jasper engine since my boat has been in my family since new my brother order it from malibu in 1989 it was all ways in storage 

Since it has some history, that to me changes the worth/value.  Now it's just a matter of how much you want to put into it.  What is your budget?  How much do you want to spend?

28 minutes ago, Transtech said:

@Woodski well besides the bad head gaskets and 2 cracked cylinder heads he claims 3 cylinders are rusted out and the  cylinder walls are pitted 

Depending on the answer to my question above, could you have it bored out?  You are buying cylinder heads and a new intake either way. 

What I'm getting at - we took our 265hp engine and bored it, stroked it, new heads & intake, SCAT crank & new rotating assembly, custom built cam, new exhaust, ran it on a dyno, etc. etc. and it turned out great.  I've never done any of this stuff (I'm a bolt off - bolt on kind of guy) and the experience thru all of the build process even up to setting the timing with my sons while on the water was a once in a lifetime kind of thing.  With the history you have of the boat, that could be cool too for you.

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Woodski

@Transtech:  I guess nothing was missed other than the crank & cam. Pretty much need a replacement short block although you can certainly go .030" over on pistons and salvage the block, add Vortec cylinder heads w/ correct intake and have a 310 hp mill.  If you want more low end torque, go with a 383 crank / rods / pistons.  You have options to consider, and if you are going the rebuild route make sure you have a shop that understands marine use (running hard when engine is cold, low speed power level, etc).

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MLBurns

If you ever pull the engine definitely get a marine oil pan, will almost double oil capacity. I don't understand why they put engines in boats with car oil pans. 

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