Mercruiser Magnum 350 Engine Specs?

barts5oh

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Aug 21, 2007
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Two weeks ago I picked up a Cobia 197SRV with a Magnum 350, and was told by the previous owner that the motor had forged internals. The boat is a 1988, the original engine was replaced with a Mercury Marine part#14152A 1 long block in 1994. This part is currently out of production so Mercury couldn't give me any specs. This engine appears to have aluminum heads. My question is if this block features 4 bolt mains, forged pistons and crank. If anyone has any info it would be greatly appreciated.
 

John_S

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Jun 21, 2004
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4,269
Re: Mercruiser Magnum 350 Engine Specs?

Forged pistons and aluminum heads indicate not a stock 350 magnum. If it is a stock engine, its from Mercs race engine line. If it is, seems like Merc would have a service manual on it.
 

Zackman

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Dec 3, 2005
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Re: Mercruiser Magnum 350 Engine Specs?

What is the engine serial number?
 

barts5oh

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Aug 21, 2007
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Re: Mercruiser Magnum 350 Engine Specs?

Haven't gotten to the serial # yet, I hear it's on the starboard side rear. There is a small tag on the rear of the port side valve cover with numbers on it, but I have to climb in with this big ole' body and try squirm in there to see wit a magnifying glass. What makes me say the heads appear to be aluminum is the fact that the front an rear surfaces of the heads where the accessory brackets bolt up to are mirror smooth, no rough casting or casting marks.
 

Bondo

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Re: Mercruiser Magnum 350 Engine Specs?

Try to put a Magnet on 1 of them..........

That'll tell you......
 

barts5oh

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Aug 21, 2007
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Re: Mercruiser Magnum 350 Engine Specs?

Okay, they're cast iron, I climbed in and saw a little rust around a threaded hole. Of all the stock small block Chevy factory heads I've seen, none has this smooth of a surface. These are also definitely not Vortecs though. As far as the serial # goes, I have to use a little emery to clean off the block to see it.
 

John_S

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Jun 21, 2004
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Re: Mercruiser Magnum 350 Engine Specs?

A stock 350 mag does not have 4-bolt mains or forged pistons, but many people "believe" it does.
 
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