3.0l merc / 4.3l merc swap

[michaelbrainard]

I have a 1985 Chris Craft scorpion 168 with the 3.0l 140hp mercruiser stern drive. Recently i saw the identical boat with the 4.3l v6. How much of a job would it be to install a 4.3l into my boat? Will outdrive bolted to the 3.0l match up to the 4.3l? Motor mounts a problem? Exhaust? Any help would be appreciated.....thanks!<br />Mike <br />michaelbrainard@hotmail.com

 

[michaelbrainard]

Re: 3.0l merc / 4.3l merc swap

Hell, while we are at it...why not drop a small block chevy in there...305-350..whatever...yea, i am getting a little crazy... but really, can it be done????

 

[CAPTBLACKSMARINE]

Re: 3.0l merc / 4.3l merc swap

yes it can be done but it is not very cheap to do .your outdrive will have the wrong gear ratio for the v-6 or v-8 and if not changed when the engine is it will be very short lived .you will also have to change the exhaust manifolds and y pipe.the motor mounts will not be the same either and will probably require some fiberglass work and depending on how the boat was built may also require some stringer work.honestly you would probably be better off to selll the boat and buy one with the engine of your choice.

 

[Walter]

Re: 3.0l merc / 4.3l merc swap

Yep...sorry to bash your hopes here. To do what you're asking would likely cost half again as much as what you've already invested in your boat. If your 3.0 is running well, either be happy with it or step up. I replaced my tired 305 with a 350, but everything bolted right up. I had to make no modifications whatsoever. Well, unless you consider swinging a bigger prop a "modification".<br /><br />Unfortunately, like the Capt. says...your situation is a bit different.<br /><br />Walt