4.3l to 5.7 conversion

[bhammer]

All, I have a 2007 boat with a 2006 Merc 4.3L MPI engine. I have a buddy who was involved in a boat accident (he hit a boulder and it ripped the boat to shreds) last year and his hull is a total loss. He didn't have full coverage insurance. So now, he has 2007 5.7 carb engine and told me I could have it for $200 if I got rid of the hull and he keeps the trailer, boat internals and the outdrive. Plus, he wants my engine to sell as well.

The engine didn't get damaged and didn't take on any water.

I have done a little Internet searching... I figure the changes I would need to make:

1. Make sure I have 12" in front to accommodate the additional length. I do.
2. Change the upper gears on the outdrive. How hard is this? I am going to see if he will swap me outdrives
3. Drill for the motor mounts
4. Make sure I am not over the Hp rating. I don't think I will be as I think you could get a 5.7 with this boat.

I am guessing that that electrical connection will be fine.... My only concern is is the added weight. The boat is already pretty stern heavy.

 

[Bondo]

Re: 4.3l to 5.7 conversion

Ayuh,... You need his outdrive if you want his motor...
Otherwise, swapping gears isn't Worth the expence...

A 350 in a 19'er can be a Handful,... Believe me.....

 

[bhammer]

Re: 4.3l to 5.7 conversion

Figured as much for the gears. I have to call him in a bit to see if he will swap drives.

The more I think about it, I may just leave well enough alone. The 4.3 is just a tad too small for the heavy 3000# boat so the extra 30hp would come in handy.

 

[45Auto]

Re: 4.3l to 5.7 conversion

Don't you read any of the threads where posters ask if a 3.0L is enough power for a 19' boat? And all the replies where they are told it's plenty?

If anything, you should be looking for a 4 cylinder to replace that V6 .....

 

[wire2]

Re: 4.3l to 5.7 conversion

You would definitely be adding weight, but nothing outrageous for a 19 footer. I believe a stock 5.7 and outdrive weighs in at ~915 lbs.

I have that combination but I took off 200 lbs with an aluminum intake, aluminum heads and replacing cast iron exhaust parts with ss headers.

On paper 4.3 to 5.7 looks like 30 hp, but to get the boat on plane, the torque figures are more important. I'm not sure what the numbers are, but with just myself in my boat, it planes in less than 1 second.

 

[bhammer]

Re: 4.3l to 5.7 conversion

Don't you read any of the threads where posters ask if a 3.0L is enough power for a 19' boat? And all the replies where they are told it's plenty?

If anything, you should be looking for a 4 cylinder to replace that V6 .....

Well, if this don't work, my next post will be about adding a blower or turbo to my 4.3. Meanwhile, I will convert to propane.

 

[bhammer]

Re: 4.3l to 5.7 conversion

You would definitely be adding weight, but nothing outrageous for a 19 footer. I believe a stock 5.7 and outdrive weighs in at ~915 lbs.

I have that combination but I took off 200 lbs with an aluminum intake, aluminum heads and replacing cast iron exhaust parts with ss headers.

On paper 4.3 to 5.7 looks like 30 hp, but to get the boat on plane, the torque figures are more important. I'm not sure what the numbers are, but with just myself in my boat, it planes in less than 1 second.

Agreed, the torque would be a big help. Adding the smart tabs made a huge difference. I didn;t get a call back from him tonight. In the last email, he had said that he may have a buyer for the entire boat as is. If it goes that way, I am sure we will see it on CL in no time as a Needs A Little TLC...

 

[45Auto]

Re: 4.3l to 5.7 conversion

well, if this don't work, my next post will be about adding a blower or turbo to my 4.3. Meanwhile, i will convert to propane. :d:d

Lmao!!!!! Good reply!

 

[PitchFork]

Re: 4.3l to 5.7 conversion

I would leave well enough alone as well especially if your 4.3L is running good with little or no problems. Although a 5.7 in a 19'er is fun it will really get up and go planes in a second when the throttle is goosed to its stop from idle. I just think it would a hassle to swap.

 

[bomar76]

Re: 4.3l to 5.7 conversion

Well, if this don't work, my next post will be about adding a blower or turbo to my 4.3. Meanwhile, I will convert to propane.

That's the spirit!!!!

.....how about all 3???

 

[bhammer]

Re: 4.3l to 5.7 conversion

That's the spirit!!!!

.....how about all 3???

Now you're thinking "out of the box" bomar... A blown 5.7 running propane.

 

[bhammer]

Re: 4.3l to 5.7 conversion

Darn, the deal is dead. He called to tell me he sold the entire boat today. I was kind of looking forward to doing it.

 

[clerihew82]

Re: 4.3l to 5.7 conversion

does he still have the outdrive?? I would be VERY interested in buying it from him! Im only 2hrs away from FT worth also

 

[infideltarget]

Re: 4.3l to 5.7 conversion

does he still have the outdrive?? I would be VERY interested in buying it from him! Im only 2hrs away from FT worth also

That was a year ago....

 

[clerihew82]

Re: 4.3l to 5.7 conversion

yes you are right and Im an idiot. For some reason I was thinking it was yesterday. Im still stuck in 2010.