260 Mercuriser in a 73 K5? Does it work...?

[Blaze`]

Gents,

Based on all of your vast knowledge, I had a quick question about a situation I am considering.

I have a 73 k5 with a worn out 350 Chevy engine and ALL new bolt on’s (headers, carb, distributor, high torque starter, etc). The long block is old and tired (read: worn rings, cam, lifters, etc).

As well I have an 83 Wellcraft Ski Boat with a relatively fresh 260 Mercruiser (360 hours since rebuild and runs SMOOTH)

However, the Wellcraft blew the engine coupling which means total removal of the Merc and transom ($1350 all labor, parts $200). The boat has had 20 good years and I think it is time to let her go.

So here is my thought/question. Pull both engines and swap them since they are both 350 long blocks. I will replace the engine in the boat with my blazer’s 350, add a new engine coupling, and clean her up and sell. Then put the Merc in my Blazer. From what I can gather, the Merc is set up to have lower end torque but other than brass here in there for water application it is the same engine.

My question is…has anyone heard of others doing this? Issues? Here is an ebay listing for a Landcruiser with a Mercruiser application, but there is no info on how it drives on the street. (http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2479574334)


Any thoughts or ideas on the swap? As well, I am also looking for an engine stand and puller to facilitate the swap if anyone has one to rent/borrow in Austin/Central Texas?

Just thought I would ask you guys first. Thanks in advance.

Donovan C. Miller Jr

[email protected]
(512) 848-0668

 

[pauly383]

It was my understanding that boat engines had better water pumps and blocks, to deal with the fresh/salt water . Or at least that is for sure nowadays. If it runs well , why not. If you can keep the boat from dying as well and sell it , even better . /forums/images/graemlins/k5.gif

 

[skelly1]

I wouldn't mess with it. Those boat engines have some strange cams. Plus, the tired one you would be putting in the boat will need different gaskets and other odds and ends. I guess if you swapped cams and changed gaskets on both motors, you might be ok, but you would save a lot of work if you just did a mild overhaul(rings, bearings, valve job, cam, lifters, etc, that is available cheap for a 350) on your truck motor and put it back in your truck.

 

[surpip]

some one told meonce that boat moters run back wards(via different cam) but im not shure about that could be tottally wrong

 

[ryoken]

couple of things...

first, make sure its the correct rotation. a reverse rotation motor will have a gear drive up front without the idler gears.

if its a raw water cooled motor (as opposed to freshwater) i wouldn't advise it if its been in saltwater.

the only difference between a marine and auto block is the freezeout plugs. cams will be a different grind, but thats not a big deal if the specs are ok... marine motors also generally dont use vacuum advance.

one of the other mechanics in our marina runs a 454 out of a boat in his Camino.

 

[84_Chevy_K10]

The only difference between a reverse rotation marine engine and a regular one is the camshaft, timing set, and firing order (and of course the starter). Change cams, put a timing chain in it, and drop a car distributor in it, set it to 1-8-4-3-6-5-7-2 and put the right starter on it and it should be ready to rock.

 

[Nonesuch]

Marine engines also have thicker cylinder walls. I have seen them bored out .120" over /forums/images/graemlins/thumb.gif

 

[Thunder]

Not much diference between Marine and auto 350s same block, heads, rotating assenbly. Cam will be similar grind to a low end RV- towing cam.with a low 0- 4000 RPM power band or less depending on engine application.
Dist are mechanical advance.
You will prolly have to swap oil pans also.
The only time you will usually get a counter rotating engine is in dual engine boats. One engine operates counter to the other to overcome torque steeer. All single engine 350 powered boats I have seen are standard rotation.
The main diference in marine Starters, alts, carbs ect is they are sealed to keep sparks and fuel from meeting each other. If that happens outside of the combustion chamber it usually results in a long swim home. So be sure to use marine parts in a boat.
Other than that they are the same.
Water pumps usually have stainless steel impellers and better seals.

 

[ryoken]

not to get too off topic but, you reminded me of single motor boats with reverse rotation motors (it was funny you mentioned it). we finally came across one a couple years ago for the first time in 15 yrs of business. /forums/images/graemlins/eek.gif for the life of me i can't remember what it was, older, smaller, something, maybe a Bertram... so yes, very rare. /forums/images/graemlins/thumb.gif

i see tons of counter rotaters, mainly cuz i work on twin 20's to 50's that are older. much rarer to see a counter rotater from the factory these days, usually taken care of in the tranny...

never had a prob with boats before i started fixing em /forums/images/graemlins/wink.gif

oh, and Tim, the starters aren't always different, sometimes they come in from the other side of the flywheel. /forums/images/graemlins/thumb.gif /forums/images/graemlins/rotfl.gif

 

[b55baron]

Back in the early '60s, a friend of mines dad pulled a 283 out of a boat and put it in his truck. It ran great. The only problem was he had one forward gear and three in reverse.