Help choosing proper intake manifold

[WELEPRO]

Good Morning,

My boat has a 96 350 in it. It orginially came with a 2bbl carb, that has gone to the way side. Rather than spending more time diagnosing its issues, I'm changing it over to a 4bbl. I have the carb, but now need an intake manifold.

Any advice on which intake to purchase? Aluminum or otherwise? Would an automotive application be ok or should I go marine?

Obviously price is always an issue, but i want it done right. Any help would be fabulous.

I love this site!

 

[Bondo]

Re: Help choosing proper intake manifold

I have the carb,

Ayuh,... What Carb,..?? It does Matter....

I'd go with the Mid/ high rise Edlebrock, as there ain't much Saltwater in Illinois...

 

[zbnutcase]

Re: Help choosing proper intake manifold

Edelbrock Performer (not Performer RPM) is a good choice, although if your raw water cooled the water passage will corrode out in 50 yrs, sooner in salt water. Its available in vortec and non vortec versions.

 

[WELEPRO]

Re: Help choosing proper intake manifold

The carb is a rebuilt 4bbl off of an older 350. '84 I believe. It has a Mercruiser tag on it, not sure if the number will help.

Boat only sees fresh water, no salt. And it's a NON-Vortec engine.

Best place to purchase the intake?

 

[Bondo]

Re: Help choosing proper intake manifold

The carb is a rebuilt 4bbl off of an older 350. '84 I believe.

Ayuh,... Sounds like an old Rottenchester....

I'd Sell it,+ buy the Edlebrock Performer carb,+ intake....
Buy it at Jegs, or Summit, or wherever you'd like...

 

[zbnutcase]

Re: Help choosing proper intake manifold

The carb is a rebuilt 4bbl off of an older 350. '84 I believe. It has a Mercruiser tag on it, not sure if the number will help.

Boat only sees fresh water, no salt. And it's a NON-Vortec engine.

Best place to purchase the intake?

Summit Racing Equipment. www.summitracing.com And I would also consider using the Edelbrock 1409 marine carb, as tuning parts more readily available

 

[WELEPRO]

Re: Help choosing proper intake manifold

Ok, I think I've decided to take Bond-O's advice, and buy a new manifold and carb. Here's what I'm looking at:

Edelbrock Performer Intake # EDL-2104
Edelbrock Performer Carb(Marine) # EDL-1409

If someone could just jump on the Summit and make sure I'm going the right route here...I'd love you forever.

Also, it appears there are several vacuum ports in the manifold...I presume I'll need to buy something to plug these?

And most importantly....since I'm a rookie with carbs, I expect that this will not be a plug and play type of deal. Am I correct in assuming there is a lot of carb tuning in my future to get my boat running the way it should?

 

[180shabah]

Re: Help choosing proper intake manifold

The 1409 is pretty goodright out of the box, with a 350 you may not need any tuning at all. If you do they are very simple to tune without removing it from the boat.

 

[John_S]

Re: Help choosing proper intake manifold

Ok, I think I've decided to take Bond-O's advice, and buy a new manifold and carb. Here's what I'm looking at:

Edelbrock Performer Intake # EDL-2104
Edelbrock Performer Carb(Marine) # EDL-1409

If someone could just jump on the Summit and make sure I'm going the right route here...I'd love you forever.

That is correct. The 2104 can take a square or spread-bore carb. Since you are going with 1409, I thought the Performer EPS would be a better match. It doesn't look like they make one for your canted style standard heads, though.

Also, it appears there are several vacuum ports in the manifold...I presume I'll need to buy something to plug these?

Vacuum and water plugs. I recommend getting a vacuum tap for the large vacuum port behind the carb. It makes for easy vacuum gauge hook-up. Keep it plugged for normal use.

And most importantly....since I'm a rookie with carbs, I expect that this will not be a plug and play type of deal. Am I correct in assuming there is a lot of carb tuning in my future to get my boat running the way it should?

The 1409 is about as easy as they come. Good chance it will run fine out of the box. They include a straight forward tuning guide with the carb.


I recommend painting the intake to avoid the white alum oxidation look, down the road. Use zinc chromate primer and paint to match engine.

 

[zbnutcase]

Re: Help choosing proper intake manifold

Every #1409 I have installed on 350s has ran great out of the box. Makes you wonder why Sierra and others even bother selling those junk reman Q-Jets when the Edelbrock is about the same price or less and its NEW!

 

[WELEPRO]

Re: Help choosing proper intake manifold

You guys are great!

It would appear that I'll need some hardware to mount the carb. The pictures don't show studs in the manifold. There are two different lengths available. 1.375 & 1.75. Anyone know which I'll need?

And as far as I can tell, I'll need a carb/manifold gasket, intake manifold gaskets, and perhaps a new flame arrester. The plugs for the vacuum ports can be purchased at my local hardware store I'd think.

I really appreciate the help.

 

[haulnazz15]

Re: Help choosing proper intake manifold

You can use the shorter studs unless you plan on bying a carb spacer. Don't forget that you'll likely need a throttle bracket, too. You will need a new fuel line/fuel filter as well. The carb will come with a gasket, but you will need an additional gasket if you get the square-bore style throttle bracket/brace.

 

[John_S]

Re: Help choosing proper intake manifold

If you want Mercruiser hard fuel line: 90 degree Elbow 22-43276 $10, Fuel line 32-8217611 $49

Mercruiser Throttle Bracket: 805359T $38

A 4-brl K&N Flame Areester and vent tubing will run $100+.

 

[haulnazz15]

Re: Help choosing proper intake manifold

Edelbrock sells a custom sized SS-braided fuel line and filter/hard line fuel relocation kit which will run about the same price as the Mercruiser hard line, but allows you a bit more flexibility on routing. It is made specifically to hook up from fuel pump to carburetor for whatever engine package you choose (SBC in your case).

I bought a generic 4bbl flame arrestor for about $40, plus another $10 for PCV tubing. A little cheaper than going the K&N route.

 

[WELEPRO]

Re: Help choosing proper intake manifold

You guys are great.

Would the throttle bracket from my old Merc carb work on the Edelbrock or are they specific to each carb?

I just jumped on Summit to order a new flame arrestor, and wouldn't ya know there's more than one option. I know the inlet on the 1409 is a 5-1/8, but there's a multitude of different overall diameters/heights, etc.

Does this matter?

 

[John_S]

Re: Help choosing proper intake manifold

You guys are great.

Would the throttle bracket from my old Merc carb work on the Edelbrock or are they specific to each carb?

Only if you make some major modifications to it. It is made to the bolt spacing on the 2brl. Mine was cast pot metal. Found a used 4brl bracket on ebay.

I just jumped on Summit to order a new flame arrestor, and wouldn't ya know there's more than one option. I know the inlet on the 1409 is a 5-1/8, but there's a multitude of different overall diameters/heights, etc.
Does this matter?

It has to fit under your dog house and not so small that it impacts air flow.

 

[WELEPRO]

Re: Help choosing proper intake manifold

So the largest I can fit under the dog house?

 

[John_S]

Re: Help choosing proper intake manifold

So the largest I can fit under the dog house?

Well, it has to fit between your risers/elbows, and other bracketry. I believe this is the one I got: http://www.knfilters.com/search/product.aspx?Prod=59-3264

What I liked, was being able to put the Mercruiser black plastic 5.7L air deflecter over the K&N to make it look stock. I doubt that the K&N has any major advantage. A used 5.7LX or 350 Mag arrester would be fine, too.

 

[180shabah]

Re: Help choosing proper intake manifold

Flame arrestors - taller and wider is better, but even a short narrow one flows pretty well.

 

[WELEPRO]

Re: Help choosing proper intake manifold

Ok, all the new parts are in. Installation will begin this evening after work, and with a little luck I'll be on the water this weekend.

I'm going to head to Home Depot with the new intake manifold to find some suitable plugs for the vaccum ports that are in it. Should I be wrapping the plugs with teflon tape or RTV or something?