5L Merc advice

[Eastboundndown]

Hello Gentleman, this is my first post so I will apologize now if I fail to follow protocol in any way. I bought a 25' double axel trailer in good shape and a 25' sunray that needs some renovations. The boat currently has a 305 carbureted merc. With a cracked block I assume. I was was not winterized and I'm NewEngland that's a major no no. So here is where I'm hoping to get some input/advice.. I was told that I can replace just the block with a 350 for a little mor hp. My buddy says it's the same size and I would still be able to swap everything over from my 305. My other concern was that I'm not sure if damage can occur in heads or intake manifold... not sure what to do at this point. I have the engine out of boat...? Any help is greatly appreciated. Thx

 

[alldodge]

My other concern was that I'm not sure if damage can occur in heads or intake manifold... not sure what to do at this point. . Thx

The 305 to 350 is a direct swap except the carb. Will need another carb of re-jet the one you have.

Don't understand the above comment, can you provide more info?

 

[Bondo]

My other concern was that I'm not sure if damage can occur in heads or intake manifold... not sure what to do at this point. I have the engine out of boat...?

Ayuh,..... Welcome Aboard,.... When replacin' a frozen busted motor, buy a Long Block crate motor, not a short block motor,....

Odds are the heads, 'n intake are also busted,.....

 

[Scott Danforth]

305 heads are for 305 motors. They have small valves for the small bores

Get the 350, go boating

 

[Eastboundndown]

Thank you for taking the time to respond and for the input.. so let me see if I got this right... 305&350 sm. Blocks r the same size but the heads and the carb(unless re-jetted) cannot be swapped from my 305 to a 350.. and someone posted about a long block. Just curious on difference other than size which I'm thinking may not fit in engine compartment. The short block only had maybe 4 or so inches of space between belts and front wall.. thanks again everyone!

 

[Bt Doctur]

short block vs long block has to to with heads and intake manifold usually . the length of the motor is not changed

 

[Bt Doctur]

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