mercruiser v8 v6 swap ?

[mxcobra]

My boat had a 898 chevy 305 setup boat is a 1979
I found this set up o craigslist for 5000$
REBUILT HIGH PERFORMANCE V6 4.3L MERCRUISER ENGINE & OUTDRIVE. COMPLETE READY TO INSTALL.
Does any one know of the ramifications of doing the swap , would it work with out mods just bolt up?

 

[zbnutcase]

Re: mercruiser v8 v6 swap ?

For one thing, there is no such thing as a "high performance" marine 4.3, and very little speed parts are available anymore. Be better off swapping your 305 anchor for a 350...and for far less than $5K

 

[Don S]

Re: mercruiser v8 v6 swap ?

I found this set up o craigslist for 5000$
REBUILT HIGH PERFORMANCE V6 4.3L MERCRUISER ENGINE & OUTDRIVE. COMPLETE READY TO INSTALL.

You don't really believe that do you ???????

 

[mxcobra]

Re: mercruiser v8 v6 swap ?

I want too, all new would sure make things nice!

 

[TilliamWe]

Re: mercruiser v8 v6 swap ?

You would have to move the front motor mounts about 4.4 inches aft in the stringers. Are your stringers flat in that area? If not, you got some fabricating to do.

 

[achris]

Re: mercruiser v8 v6 swap ?

I did exactly that swap for a friend of mine. His old (1977) '898' out, and my old (1994) 4.3LX (complete including transom assembly and drive) into his 23 foot half cabin boat. Far better fuel consumption, and he picked up 6 knots on the top speed. He is over the moon with the result.

You will also have to make sure the engine mountings (on the hull) extend far enough back to accommodate the shorter engine block. As TW said, 4.4" to be exact.... You'll also have to drill 2 new holes at the top of the transom cutout. That package needs to include the transom plates too. Neither the engine nor the drive will bolt up to your existing transom assembly....

Chris....

 

[mxcobra]

Re: mercruiser v8 v6 swap ?

Motor mounts are not a problem, they are curently under fabracation,
The new transom is cut and installed for the curent 898.
If im reading this right the key hole and bolt holes are the same??
The current 898 will be a grand or more to get back up to snuff.
From my exp. a v6 will have a higher rpm then a v8

 

[Bondo]

Re: mercruiser v8 v6 swap ?

From my exp. a v6 will have a higher rpm then a v8

Nope,... They're both propped to 4800 rpms...

 

[Howard Sterndrive]

Re: mercruiser v8 v6 swap ?

I'd recommend this before some unknown rebuild with no warranty... a 4.3 with all the bells and whistles and same overall power as a 305 4 bbl
http://www.ebay.com/itm/MERCURY-4-3...at_Parts_Accessories_Gear&hash=item2c583cad0d

 

[achris]

Re: mercruiser v8 v6 swap ?

..If im reading this right the key hole and bolt holes are the same??

Yes, the cut out is the same, but ....

... You'll also have to drill 2 new holes at the top of the transom cutout.....

I'd recommend this before some unknown rebuild with no warranty... a 4.3 with all the bells and whistles and same overall power as a 305 4 bbl
http://www.ebay.com/itm/MERCURY-4-3L...item2c583cad0d

Couple of issues with this unit.
1. It's engine only. This engine will NOT bolt up to the 898 inner transom plate.
2. Get a year of build. If it's 2006, run away!!!!

Chris.....

 

[Howard Sterndrive]

Re: mercruiser v8 v6 swap ?

Yes, the cut out is the same, but ....

Couple of issues with this unit.
1. It's engine only. This engine will NOT bolt up to the 898 inner transom plate.
2. Get a year of build. If it's 2006, run away!!!!
Chris.....

I was thinking he could just use the flywheel cover off the 898/305 on the 4.3.
aren't all chevy 90 degree motors the same in that regard?
it's 2008 and I suspect it would work just fine with the 898 drive gearing.

it would be a no brainer for me to put a new '08 MPI motor in there as far as adding value to the boat over an old carbed 4.3 that has been rebuilt.

either way, I think if the OP wanted used, he should keep shopping for a 305 or 5.7 and maybe a donor boat unless he has some goal of increased fuel economy or wants MPI for startability

 

[Silvertip]

Re: mercruiser v8 v6 swap ?

The term "Hi-Performance 4.3" needs to be investigated to determine exactly what was done to it to make it "Hi-performance". You quite possibly could end up with an engine that has a bunch of aftermarket car parts that in a car would make it "Hi-performance" but in a boat would not get out of its own way. What cam, what compression, what heads and valve work was done, what manifold and carburetion???????