Recommendation for rebuilt cylinder heads

britandy

Member
Aug 19, 2019
39
Boat Info
340 Sundancer 2000
Engines
Mercrusier 7.4 MPI, inboard, V drives
Last winter when I replaced my exhaust manifolds, elbows and risers, I noticed severe corrosion in some of the exhaust ports, but at that time did not want to get into removing/replacing heads. Of course this issue bugged me all season and I decided this winter to replace the heads. Today I removed the heads from the port engine and took a few pictures for all to see.
IMG_8178.jpg IMG_8179.jpg IMG_8180.jpg
I am pretty sure the heads are toast, corrosion is so bad in a couple of ports that chunks of metal flaked off.
I wonder if anyone has a recommendation for a supplier for rebuilt/remanufactured heads?
My engines are 7.4 MPI L29 Gen VI. They are 20 years old.

I have owned the boat for about 18 months. It appears moisture sits in the exhaust manifolds after the engines are turned off. In fact when removing my only one year old manifolds there were tiny pools of water sitting in each manifold exhaust port. I had found the same when I removed the old ones last winter. I assume a poor design that unfortunately over many years leads to this corrosion. The water must be condensate, I think? With all new manifolds, risers, elbows and Mercruiser gaskets I don't see where else it would come from.
 
Last winter when I replaced my exhaust manifolds, elbows and risers, I noticed severe corrosion in some of the exhaust ports, but at that time did not want to get into removing/replacing heads. Of course this issue bugged me all season and I decided this winter to replace the heads. Today I removed the heads from the port engine and took a few pictures for all to see.
View attachment 97488 View attachment 97489 View attachment 97490
I am pretty sure the heads are toast, corrosion is so bad in a couple of ports that chunks of metal flaked off.
I wonder if anyone has a recommendation for a supplier for rebuilt/remanufactured heads?
My engines are 7.4 MPI L29 Gen VI. They are 20 years old.

I have owned the boat for about 18 months. It appears moisture sits in the exhaust manifolds after the engines are turned off. In fact when removing my only one year old manifolds there were tiny pools of water sitting in each manifold exhaust port. I had found the same when I removed the old ones last winter. I assume a poor design that unfortunately over many years leads to this corrosion. The water must be condensate, I think? With all new manifolds, risers, elbows and Mercruiser gaskets I don't see where else it would come from.
I have a mint set of heads from my L29 that I just had redone if you're interested. All painted already too. I'll sell them for very short money. I decided to go with a different casting for more compression. Where are you?

IMG_20201109_164432.jpg
 
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I have a mint set of heads from my L29 that I just had redone if you're interested. All painted already too. I'll sell them for very short money. I decided to go with a different casting for more compression. Where are you?
I am in Pasadena Maryland. What are the casting numbers? 279?
 
HawkX66, thanks for the offer but I will need 279 heads.
 
HawkX66, thanks for the offer but I will need 279 heads.
Like me, it's what you would like, but not what you need. I can completely appreciate that though. Good luck in your search.
 
Shenanigans77, thanks for your recommendation. They are out of my budget, new would be nice but I have been looking at rebuilt/reconditioned heads, they are around $500 a piece.
 
scoflaw, you are correct, I missed that! That is a good price then. So far I am finding out that for the new heads, the castings are made in China, probably no big surprise there. Now that might not be an issue, but something to consider. My thinking is if I go with rebuilt then the castings most likely would be true GM cast and US made. Just a theory!
 
Eq heads are cast at a foundry in New Zealand. A lot of GM’s current cast heads come out of Mexico
 
shenanigans77, that is good to know, and I really appreciate your comments. As you already know replacing heads takes some research. These EQ heads are looking more attractive.
 
shenanigans77, another question for you then.....did you use all Mercruiser gaskets (head, intake, rocker covers) or go with any Fel Pro?
 
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K
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Been there, I feel your pain. I still had honing marks at 1000hrs so opted to just go new top ends. They use zero oil and just purr. Im hoping for another 1000 hrs.
 
shenanigans77, another question for you then.....did you use all Mercruiser gaskets (head, intake, rocker covers) or go with any Fel Pro?
Felpro marine....Superior to the gm graphite imo. I have the mpi motors so I went with the metal/rubber felpro instead of the plastic/rubber stock GM for the intake. Replaced the head bolts with ARP as well.
 
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Thanks, again I appreciate all your comments. I am getting close to hitting that buy button! I will look for the Fel Pro marine gaskets. I like that you painted the heads as well. Had not figured that in, another job to do!
 
That link is for a pair for $1080. Very good price
Talkin out my butt here, but Scof, with a MAG MPI, shouldn't those be rectangle ports? Pic on Ebay shows ovals.
I'm right behind him for my tired Port side......
BBC heads on Ebay.jpg
 

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