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Which style is the best exhaust manifold?

Chris Rohde

Chris Rohde

Regular Contributor
It appears that there are two types or replacement manifolds that will fit my application. One has a tube where the water enters below each opening, and the other has the water running right into the side of the main body of the manifold. My question simply is, GENERALLY SPEAKING what's the real reason for the difference, and is one version better than the other?

s-l1600 (1).jpg s-l1600.jpg

Thanks!!
 
Chris Rohde said:
It appears that there are two types or replacement manifolds that will fit my application. One has a tube where the water enters below each opening, and the other has the water running right into the side of the main body of the manifold. My question simply is, GENERALLY SPEAKING what's the real reason for the difference, and is one version better than the other?

View attachment 19362 View attachment 19363

Thanks!!
Click to expand...


Chris, I believe that either of these will work.

With the GLM manifolds, you can see how the seawater is ported (via the cast tube affair down low) into the manifold.
It is then directed towards each exhaust runner just prior to entering the main chamber area.
This makes for (what I see) as very good and even heat dissipation.

I also see ported Elbows. If you should have a Full Closed Cooling System, this would be imperative.



I can't see the brand name on the second set.
This style was commonly used with the 335 series (5.0L or 5.8L) Ford Engines. They would also work.

However, with these I am not seeing ported Elbows.


Suggestion:
use a light coating of "Automotive" Never-Seez on the manifold bolts (going into the cylinder heads)

never seez .jpg

DO NOT Use the Marine grade Anti-Seize!
 
RicardoMarine said:
Chris, I believe that either of these will work.

With the GLM manifolds, you can see how the seawater is ported (via the cast tube affair down low) into the manifold.
It is then directed towards each exhaust runner just prior to entering the main chamber area.
This makes for (what I see) as very good and even heat dissipation.

I also see ported Elbows. If you should have a Full Closed Cooling System, this would be imperative.



I can't see the brand name on the second set.
This style was commonly used with the 335 series (5.0L or 5.8L) Ford Engines. They would also work.

However, with these I am not seeing ported Elbows.


Suggestion:
use a light coating of "Automotive" Never-Seez on the manifold bolts (going into the cylinder heads)

View attachment 19364

DO NOT Use the Marine grade Anti-Seize!
Click to expand...

NEVER USE GLM. We call them....GOOD LUCK MARINE parts.

Price out the oem parts from Volvo Penta....They will be a few dollars more.
 
My only concern with the one with the tube at the bottom is that as the rust and corrosion sets in, that could really restrict water flow toward the back of the manifold.
 
In reality, how often does the elbow go bad? I'm thinking of re-using my old ones. Of course I will inspect them. Last time I had one off, it looked like it had a fair amount of rust on the inside, but nothing significant like the manifolds do. Mating surface looked good, I did take a sanding block to it before I put it back together and have had no problems using the metal volvo gaskets and a coat of copper spray on the manifold side. I will of course inspect them again while replacing the manifolds. Seeing as they really don't allow water to sit in them like the manifolds do, and this is a non-salt water boat, I'm thinking I will be fine. I'm going to go with Barr manifolds at $275 a piece including shipping. Barr does not make my elbow. So I have two options if I did want to purchase new. GLM at $160 a piece, good price but supposedly scary lack of quality, or VP @ anywhere from $300-$650 each!!! This seems to be the bummer with owning a Ford EFI engine.
 
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