4.3LX to 350, Merc

[kcjefff]

So my 4.3L LX (205hp) block is cracked. I am looking for the cheapest way to get back on the water for a few years until I am ready to upgrade. I know a guy who has a 350 that dropped a valve. He says I can have it for $250 and I can buy parts at whatever cost I can find them for him to install. What parts are swappable between the two (alternator/starter/carb/etc)? Will my drive work, even though the ratios are going to be a little different? Also, it is a truck motor we are going to marinize. So far I have read we need SS head gaskets, brass plugs, and new manifolds. What else?

 

[kcjefff]

Re: 4.3LX to 350, Merc

Bumping my own thread for lots of views, but no replies. I'd like to get an idea at what I am looking at. It looks like to me that the starter, alternator, and carb should all move over perfectly. What about the water pump? Where's a good place to get manifolds?

And, btw, we are putting a new cam in it, too.

 

[Haut Medoc]

Re: 4.3LX to 350, Merc

http://www.rapidomarine.com/default.aspx?p=/engines/default.aspx
This would be the cheapest, easiest way, IMO.......​

 

[kcjefff]

Re: 4.3LX to 350, Merc

Thanks. More specifically though, what in outfitting this 350 is going to cost me the $2000 difference between that and a new/reman 4.3 block? I paid 3500 for the boat and after I buy and ship the block, then have someone install it, I am looking at another $3500. Whereas with the 350. We have the engine and can have it running for ~300, install for say... 700 and I am sitting at 1k. Keep in mind, I only plan on keeping the boat for ~3 more years and we are less than 100hr/year (probably far less) boaters on the lake of the ozarks.

 

[whywhyzed]

Re: 4.3LX to 350, Merc

what in outfitting this 350 is going to cost me the $2000 difference between that and a new/reman 4.3 block?

Exhaust manifolds. - $1500
New outdrive with V8 gear ratio - $1500

There's $3K just for those 2 items.

Will your carb fit the intake on the 350? If not, carb = $400
If so, reworking carb for V8 = $125

Marine V8 distributor - $350

I am looking for the cheapest way to get back on the water for a few years until I am ready to upgrade.

Far and away, the cheapest way is to buy another boat with the same motor that runs, but is missing the outdrive, and racoons have moved in, and the stringers are rotten and someone might even PAY you to haul it away

Second cheapest way - go buy a 4.3 Astrovan or S10 engine from a similar year from the wreckers and strip it to the long block, swap in brass core plugs and swap all marine stuff over and install.

 

[Haut Medoc]

Re: 4.3LX to 350, Merc

I'm seeing $1600 for a long block, delivered, that all of your externals will bolt right onto.....
As opposed to a 350 of unknown quality, rings , compression, etc....
That you will need a upper(at least) for the drive......
Basically all of the stuff that KJD mentions, & some others that that might pop up....
I believe you will need to move the front motor mounts as well...
Will a V8 fit in the V6 hole that is under your motor cover?...
If ya got all summer to cobble something together, go for it, if ya wanna be on the water this summer........well........​

 

[kcjefff]

Re: 4.3LX to 350, Merc

Second cheapest way - go buy a 4.3 Astrovan or S10 engine from a similar year from the wreckers and strip it to the long block, swap in brass core plugs and swap all marine stuff over and install.

Actually, funny that you mention that. I also have a lead on an Astrovan engine for $250, but the 350 was enticing if it would work.

 

[Haut Medoc]

Re: 4.3LX to 350, Merc

Go for the bolt in replacement, you will save a ton of $.......​

 

[kcjefff]

Re: 4.3LX to 350, Merc

By bolt in replacement, do you mean the Van or the reman?

 

[Haut Medoc]

Re: 4.3LX to 350, Merc

Either one.....
You just have to make sure the van has the right engine......
That would be cheaper if the engine is good.....
With the rebuilt, you get a warranty.....
I have heard good things about Rapido.....
It's your choice.....
I'd do a compression test on the van before I bought it though.....​

 

[whywhyzed]

Re: 4.3LX to 350, Merc

make sure the astro engine has provision for mechanical fuel pump if your boat does. similar year best bet.

 

[kcjefff]

Re: 4.3LX to 350, Merc

Thanks very much, guys.

 

[kcjefff]

Re: 4.3LX to 350, Merc

One more question, sorry for the trouble. If I were to decide to do the 350 instead of the 4.3 (because I know more about the 350 in question) Couldn't I just swap the upper, not the whole drive? Btw, I need new manifolds either way because the current ones are trash, so that cost is the same regardless. Just trying to compare apples to apples.

Also, for my own education, because I like learning about this stuff. What needs reworked on the carb, and what is the difference between an auto and marine distributor? I have learned about starters/alternators/etc, but not that.

 

[Haut Medoc]

Re: 4.3LX to 350, Merc

Yes, you can just swap the upper if it is the same model....
I think I said that in a previous post.....
The carb would need to be re jetted.....
A marine dist does not have vacuum advance, it is mechanical......​

 

[kcjefff]

Re: 4.3LX to 350, Merc

Thanks again.