260 Blew

[backwater dawg]

I have a 1988 Merc 260--5.7 and the first time out-300 yards under power-BANG---bad deal---I sat at the dock--checking things--ran perfect--normal oil pressure-temp fine--ran up on plane---BANG---rods hanging out of the oil pan--pieces of block in the bildge---ish---now my plan is to pull the engine--take all the marine parts--mani-carb-ect- and find a auto block that will work--it's an old boat and I can't spend the money on a new one--any suggestions on the age and type of block I should be looking for---truck block I assume--and any other ideas---Thanks--Steve

 

[WizeOne]

Re: 260 Blew

Bad luck but good plan bd. You will need to change the freeze plugs to brass and if you boat in salt water you'll have to pull the heads and install the SS ringed head gaskets.

I'm sure the Chebby experts will be right along for all the other details.

 

[Haut Medoc]

Re: 260 Blew

First check your engine serial #.....
GM went from the two piece to one piece rear main seal in 1986, I believe & sometimes the hull year is not the engine year.....
So as a precaution, make sure you know what you have....
You will need a truck or van engine or you will need to change the cam......
You will need to replace the head gaskets & core plugs if you have a raw water cooling system......
I would change the core plugs anyway, regardless.....

 

[KnottyBuoyz]

Re: 260 Blew

I wouldn't go to all that trouble, just sue country_bumpkin, he's used to it!

http://forums.iboats.com/showthread.php?t=207127

Sorry CB couldn't let that opportunity slip past so easy!

Ok seriously now. Do they make a 4 bolt main 350? I've often wondered if I blew mine up what I'd do. It's a VP AQ271A which is the same engine that's in my '87 IROC. Pretty common so a replacement long block should be easy, and relatively cheap to find. I think Michigan Motorz lists them for a lil' over $2K.

 

[Silvertip]

Re: 260 Blew

Trucks have 4-bolt main 350's and they also have a cam that is fairly close to a marine cam. An IROC motor will not have a suitable cam.

 

[backwater dawg]

Re: 260 Blew

I bought the boat new in 1988---so I assume the engine is a 88---I will check the ser #--where is it and what am I looking for--thanks

 

[backwater dawg]

Re: 260 Blew

What year truck block should I be looking for??

 

[Haut Medoc]

Re: 260 Blew

I bought the boat new in 1988---so I assume the engine is a 88---I will check the ser #--where is it and what am I looking for--thanks

There should be a plate just aft of the starter....

 

[Haut Medoc]

Re: 260 Blew

'87+......

 

[backwater dawg]

Re: 260 Blew

So from what I'm hearing I need a post 1987 GM truck block--2 bolt or 4--I assume I need to change the intake man-carb-heads??--can I use the existing cam or put the one out of the marine engine??-Thanks

 

[Bondo]

Re: 260 Blew

Ayuh,....

Because the trucks are EFI,.. Yes the Intake is different.....
The Heads will work Just Fine,...
As will the Cam...

 

[J JACKSON]

Re: 260 Blew

i build a lot of racing engines and i people always want a 4 bolt main block and truthfully a 2 bolt has a thicker casting around the mains. when you are building a high hp motor 500+ we take 2 bolt blocks and have 4 bolt billet caps installed on them. that being said a 2 bolt block in a boat would be fine.