4.3 liter to 5.7 liter swap??

[JustMrWill]

Just found out that due to an unfortunate accident, I may be able to get my hands on a pratically new (Under 10 hours) 5.7 liter v8 engine (boat sank in salt water, engine pulled within hours of water submersion, water removed and whole engine oiled and moving freely - eletronic ignition and fuel injection toasted). If the price is right, how hard would it be to replace my 1987 OMC 4.3 liter v6 with this? Would my outdrive be able to handle the extra power? Would the added weight be a problem on my 21' Regal Majestic? Anything else I should be concerned with?<br /><br />-JustMrWill

 

[tommays]

Re: 4.3 liter to 5.7 liter swap??

if the motor was not run ASAP after it was recovered it has most likely has rust damage in areas that can not be seen and wont show up until the motor runs under power oiling is only a first step in saveing a motor<br /><br />if the boat was recovered what happened to it and why was the motor not reused<br /><br />i think your 87 omc drive would be beging for mercy with a 5.7 powering it<br /><br />tommays

 

[JustMrWill]

Re: 4.3 liter to 5.7 liter swap??

I'm gonna find outthe rest of the story..it is a dive club buddy's boat...don't know exactly what happened..I know insurance is involved so I am assuming the boat itself was a total loss. I need to find out alos if the outdrive was salvaged...and more specs on this engine. So, my current outdrive would not be happy with that much power?

 

[Bob_VT]

Re: 4.3 liter to 5.7 liter swap??

If you are asking about the alpha 1 outdrive yes it will handle the power but the gears will have to be changed. You would pick up more weight and more power but the increase may not be as substantial as you think.<br /><br />Bob

 

[dcpcccrc]

Re: 4.3 liter to 5.7 liter swap??

i am doing the same thing right now changing my 4.3 to a 350 chevy thats the good thing about chevys the all use the same pattern that outdrive should hold up. mine they told me to start by changing to a bigger prop and eventually if not satisfied change the gears another guy on here said he has done it and loves it he said it is an awesome ski/wakeboard boat and he can hit 50 mph like it is nothing

 

[tommays]

Re: 4.3 liter to 5.7 liter swap??

read carefuly he wants to reuse the 1987 omc outdrive which i feel would not take the power<br /><br />tommays

 

[JustMrWill]

Re: 4.3 liter to 5.7 liter swap??

So,<br />What I am hearing, it that I would be better off (but a good deal poorer) to replace outdrive if I wanted to go bigger engine. Now the question would be - what outdrive should I be looking at?<br /><br />-JustMrWill

 

[Boatin Bob]

Re: 4.3 liter to 5.7 liter swap??

The Cobra drive should be fine with a 350 260hp or how much HP is this 350? You may have to change gears or at least the prop but as long as it's not putting out 300 +hp should be OK. If you change drives you are going to need transom work to put in a Merc or there is a kit through Volvo that will let you bolt up one of their drives.

 

[Doug Durako]

Re: 4.3 liter to 5.7 liter swap??

There is a reason insurance companies do not pay to rebuild motors that have gone under. They do not do it with autos, either.<br /><br />Many hidden issues, but if you are willing to take the risk, good luck. Is he giving you the motor? I would not pay anything for it. Why did the insurance company not get the salvage value for the motor?<br /><br />If it were me, I would do a complete tear down, or have a mechanic do it this winter.<br /><br />Your boat should handle it (check YOUR insurance coverage, some carriers limit the horsepower they will cover on a 21-foot vessel).<br /><br />good luck!