Intake Manifold

[nfpa55]

I am a first time boat owner and rebuilding the engine (Mercruiser MCM 350 Magnum Alpha One. I purchased an intake manifold and mistakenly ordered the wrong one (Vortec). I am having a very difficult time trying to figure out which one I need to purchase. I tried to attach photo's of my engine but the site would not allow me, (unkown error). My engine has the Quadrajet carburetor as well. Any assistance would be GREATLY appreciated.

 

[wellcraft-classic210]

The quick answer is their are 2 bolt patterns

You would need a 12 bolt intake for older head designs vs 8 bolt intake for vortec.

Lots of info on google // Good luck

 

[Bondo]

The quick answer is their are 2 bolt patterns

Ayuh,....... Welcome Aboard,..... Actually, there are 3 patterns,......

Early SBCs use 12 bolts, all at the same angle,.......

1986 to 1996 heads use 12 bolts, but the center 4 are at an odd angle,.....

Then 1996 to current are Vortec heads which use only 8 bolts,.....

 

[San_Diego_SeaRay]

Do you know the serial number? If so:

1. Go to the Mercury Parts Catalog
2. Launch Parts Catalog
3. Enter your serial number in the top header section and hit the magnifying glass "Search" icon
4. There will be models that are listed in the right hand window. Find yours and click on the link
5. The left window will be populated with a breakdown of engine components. Click on the Intake Manifold listing.
6. An exploded view should show up with each part listed under a number, and a table showing the corresponding part number. That part number is what you're looking for.

 

[offthehook2]

I have both style 12 bolt manifolds if you need one and might be interested in the vortec style you have

 

[Scott Danforth]

I am a first time boat owner and rebuilding the engine (Mercruiser MCM 350 Magnum Alpha One. I purchased an intake manifold and mistakenly ordered the wrong one (Vortec). I am having a very difficult time trying to figure out which one I need to purchase. I tried to attach photo's of my engine but the site would not allow me, (unkown error). My engine has the Quadrajet carburetor as well. Any assistance would be GREATLY appreciated.

First, welcome aboard

if you read the rules you agreed to, you cant upload photos until your 4th post. so post a few times. after that, the photos must be below 700k in size, so if you are taking them with your phone, email them to yourself and reduce them to 25% or smaller

I would upgrade to vortec heads. a new set of vortec heads is $600, a good quality used set with adjustable valve train is under $400

 

[nfpa55]

Thank you all for your assistance. I ended up getting the correct manifold to find out the lower unit had a crack in the block.
: (

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I purchased the boat in December which has a 350 Mercruiser 5.7L Magnum Alpha One. I didn't realize it had a crack in the block and had to replace the engine. Before pulling the engine out the trim cylinders and trim worked fine, now that I swapped the engine out I have no power to the outdrive and cant get it to go up and down neither with the trailer switch or the trim button on the throttle control. I believe I have missed a wire somewhere or connected it back wrong. Any assistance would be greatly appreciated. Thank you.

 

[Bt Doctur]

do you have the main power wires from the pump connected to the battery,

 

[nfpa55]

Lol... I do not believe I do ! I hooked the batteries up last night and do not think I hooked the main power wires up, I am going to check when I get home from work today, thank you Bt Doctur !

 

[NHGuy]

Make sure you have a good ground. First time I reinstalled an engine I left off the trim tab ground on my boat. That's not the same,but similar.