difference between car intake manifolds and boat

delsol

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whats the difference between car and boat intakes 89 5.7 merc
thanks
bob
 

Scaaty

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Re: difference between car intake manifolds and boat

Probably nothing...
 

Bondo

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Re: difference between car intake manifolds and boat

You'll have to be Much More Specific than That.......
 

delsol

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Re: difference between car intake manifolds and boat

my 89 cast iron. i think thats what is made of is rusty bad. i am getting a rebuilt 5.7 350 for the motor, i am not loaded with money. i live near lots of car junk yards. if its the same intake or will work i want to replace it over the winter..also ..also i thought about looking at summit racing to see if they had a new cheap mani
bob
 

John_S

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Re: difference between car intake manifolds and boat

As long as your rebuilt is the same vintage, you have the canted center bolts on middle intake bolts. This was a change that happened around '87, which means there will be few junkyard manifolds available. Very few if any carbs on cars/trucks after that year. You will want to stay with a cast-iron if you are raw-water cooled. GM has a cast-iron dual-plane highrise for around $200. Excellent manifold if it will fit under your dog house. There are a number of aluminum manifolds, if you are freshwater cooled or don't boat in the salt.

I have an Edelbrock 2104 Performer intake manifold that fits your year heads. It is new and has never been installed on an engine. I primed it with zinc chromate and painted black. $100 + shipping. Jegs = $160.
 

Bondo

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Re: difference between car intake manifolds and boat

Ayuh,....... I'd say John has you Pretty Well Covered,.....

I'll just add,.... Don't get a Single plain manifold,.... It'll be a Dog in a boat,......
Stick with a Dual plane,... That's the Torque Builder......

ebay Might be a good place to Save some Money.........
 

delsol

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Re: difference between car intake manifolds and boat

are the stock ones duel plane. can someone better describe duel plane
thanks
bob
 

Bondo

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Re: difference between car intake manifolds and boat

Ayuh,...........Stockers are Dual Plane.......

They're the 1s that Look like there's 2 levels @ 2 barrels Each,... Side by Side......
Rather than a Common Hole for 4 barrels......
 

Scaaty

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Re: difference between car intake manifolds and boat

I have an Aluminum Intake on my big boat (VP 350) in salt for years....no prob....just stick a pencil zinc in it, replace yearly.
 

RandyJ

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Re: difference between car intake manifolds and boat

Scaaty said:
I have an Aluminum Intake on my big boat (VP 350) in salt for years....no prob....just stick a pencil zinc in it, replace yearly.

Not familiar with saltwater operations or anodes... what is meant by or how do you "stick a pencil zinc in it"?
 

Reel Poor

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Re: difference between car intake manifolds and boat

RandyJ said:
Scaaty said:
I have an Aluminum Intake on my big boat (VP 350) in salt for years....no prob....just stick a pencil zinc in it, replace yearly.

Not familiar with saltwater operations or anodes... what is meant by or how do you "stick a pencil zinc in it"?

Look here You can screw them into the intake manifold thru a water plug.

 
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Re: difference between car intake manifolds and boat

there is nothing differant in the size or bolt patterns between a marine application or auto intake.

SOME marine intakes have a brass lined water jacket, but not all. most marine applications are cast iron so the expansion rate is the same as the block to minimize gasket leaks at high tempatures.

an aftermarket alluminum intake will work just fine. keep in mind, marine applications are about torque, not rpms. so you dont want a tunnel ram, or high rise intake. duel plane low rise intakes will serve you better.

if you get an alluminum intake, dont forget to put an anode on it to controll corrosion
 

Don S

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Re: difference between car intake manifolds and boat

if you get an alluminum intake, dont forget to put an anode on it to controll corrosion

Could you explain please.
I layed one on my manifold and it didn't do anything.
 

Scaaty

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Re: difference between car intake manifolds and boat

Pencil zincs are sold in all sizes at Boaters World among others. Come with or without the Brass plug. They simply screw into the plug. Then into a port in the manifold. You might need to cut them down so they don't bottom out. This is a pic of mine (350/Aluminum Manifold) after 6 weeks in salt (3 other boats, plus I was on a month long road trip, so it only sat in the slip for a bit.

PICT0015.jpg
 

Autotech1

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Re: difference between car intake manifolds and boat

Dual plane manifolds have a seperate plenum for each side of the carburetor. One plenum feeds #s 1,4,6,and7, while the other plenum feeds #s 2,3,5,and8.

chevyjunk003.jpg


chevyjunk002.jpg



Single plane manifolds have only one plenum feeding all the cylinders.

chevyjunk001.jpg
 
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