Cylinder head hunt. . . SBC #906 Mercruiser 5.7

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TerryW2

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Hi Folks,

Anyone out there know where I can get a couple of cylinder heads for a Mercruiser 5.7 circa 96 onward. These are #906 type heads.

Often companies that do repowers get a stock of old heads during the Winter months from engines whose blocks froze. Trouble is I can't find anyone doing this kind of work round here. Maybe it is just too warm with global warming.

Terry
 
TerryW2 said:
Hi Folks,

Anyone out there know where I can get a couple of cylinder heads for a Mercruiser 5.7 circa 96 onward. These are #906 type heads.

Often companies that do repowers get a stock of old heads during the Winter months from engines whose blocks froze. Trouble is I can't find anyone doing this kind of work round here. Maybe it is just too warm with global warming.

Terry
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I don't know if this will help....http://www.realsteel.co.uk/
 
neale said:
Did they change in the 90's? I think I have a couple of heads from a GM 350 5.7 litre in the garage. They would be from around 1990 though.
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Very interested if they are #906 heads. The casting number runs across the heads on the top side of the head between rocker posts at one end. It is a 6 or 7 digit number but only the last 3 matter. Any year 906 head will work. I would even say the older the better. There is less chance of them being cast from re-used metal. Feel free to PM me a price and address and I'll try to arrange to come over and see them sometime.

Terry
 
Hi Neale I think you will find the heads maybe different. If you had the 8 intake manifold (gen +) they would be ok. Terry have one head removed that requires clean up may have 2 more. Going to have a dig about over the weekend.

Will give you a call tomorrow.
 
mercuryman said:
Hi Neale I think you will find the heads maybe different. If you had the 8 intake manifold (gen +) they would be ok. Terry have one head removed that requires clean up may have 2 more. Going to have a dig about over the weekend.

Will give you a call tomorrow.
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Very many thanks. The help is really appreciated.

Terry
 
I have a pair of heads off a 1999 5.0 which are absolutely mint c/w valves etc,

engine had 100 hours on when it got frosted im not sure if the 5.0 & 5.7 heads are the same but id expect them to be someone can maybe advise pm me if you think they might suit your purpose

ken
 
KEN_NUNN said:
I have a pair of heads off a 1999 5.0 which are absolutely mint c/w valves etc,

engine had 100 hours on when it got frosted im not sure if the 5.0 & 5.7 heads are the same but id expect them to be someone can maybe advise pm me if you think they might suit your purpose

ken
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Hi Ken,

The small block chevy head has been manufactured in tens of variants over the years. The differences are in valve size, combustion chamber volume, position of the drillings that hold the ancilliaries, position of the screws that hold the rocker box, some are designed to use a vortec intake manifold and some are not.

I have a set of tables that I use to see whether a head will work ok. The key piece of information is the cylinder head casting number that is on the upper side of the head between two rocker posts at one end. It is a 5 or 6 digit number. The last three digits are the important ones. Mine say 906 so they are type 906 heads. There are few other numbers molded in that give the day, month and year of manufacture and say something like D156 which is April 15th 19x6. You have to estimate the x. D is the month (A = jan, B = feb etc)

Most 5.0L heads can be bolted on the base engine but it may mean a lot of work to replace the intake, move power steering equipment, serpentine idler pulley etc. Plus, the gas flow is not so good and the compression ratio rises due to the smaller combustion chamber size. This is bad on a marine engine that works at 3/4 load all the time. I can tell what will work, more or less, from the casting number and few minutes working with my spreasheets.

Many thanks.

Terry.
 
Hi Terry I'm working on a DSV in the north sea just now

These are pre vortec heads & had the serpentine belt system I can get my wife to pop in to the workshop in the week & get numbers off the heads & pictures etc if you think they might work

I,m due home next week so could organise sending them ect then

let me know if you want further info

regards
ken
 
KEN_NUNN said:
Hi Terry I'm working on a DSV in the north sea just now

These are pre vortec heads & had the serpentine belt system I can get my wife to pop in to the workshop in the week & get numbers off the heads & pictures etc if you think they might work

I,m due home next week so could organise sending them ect then

let me know if you want further info

regards
ken
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Hi Ken,

I don't imagine pre-vortec heads will work without a lot of work. Don't rush around over this please. Next week is absolutely fine. The boats isn't going anywhere . . .

Many thanks

Terry
 
KEN_NUNN said:
I assumed yours was pre vortec being 1996? vortec is 1999 onwards

ken
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Hi Ken,

Mine is a vortec (8 bolt intake). I am pretty sure Vortec came out in 1996. My old tub is a 1998 2452. The original engine was a 5.0L that I swapped for a 5.7. I successfully re-used the intake and carb.

http://www.crankshaftcoalition.com/wiki/Vortec_L31_cylinder_head

Here is a view of the heads looking down. . .

inletManifoldOffsmall.jpg

This is the end of a #906 head where the ancilliaries bolt on. Note the single camel hump . . .

906_VORTEC_END_ID.jpg

There is a reasonable chance that they are 906 or the equivalent 062 head given the year (1999). Fingers crossed.

Terry
 
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The V6 had the balance shaft. V8 Vortec or Gen + has redesigned heads loosing the exhaust passage to warm up the intake manifold to heat the choke.Also had flat tappets.

Vortec(gen+) lost this and went to an 8 bolt intake with parallel bolts. Also improved roller lifter tappets.

Terry call in morning think the 2 heads I was going to use for my engine are what your after. Will check casting numbers.
 
mercuryman said:
The V6 had the balance shaft. V8 Vortec or Gen + has redesigned heads loosing the exhaust passage to warm up the intake manifold to heat the choke.Also had flat tappets.

Vortec(gen+) lost this and went to an 8 bolt intake with parallel bolts. Also improved roller lifter tappets.

Terry call in morning think the 2 heads I was going to use for my engine are what your after. Will check casting numbers.
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just researched that! the heads I have have paralel bolts & engine had roller lifters so probably the same let me know if you dont get sorted & i'll check mine when i'm home

ken
 
Hi Ken,

I'd appreciate if you could check your heads for me when you get home.

Vortec - confusion all the way. The name is used to refer to the GM engines from 1988 onward that used the vortex technology. . .

Terry
 
There is a company called Chera Marine in Bradford that some remanufactured heads. I wonder if anyone has had dealings with them. They have no web presence that I can find that is a bit worrying for someone who is already dealing with a warranty issue.

Terry
 
Hi Terry yes delt with chera marine it took me 12 months to get my money back for the incorrect items he supplied !

ended up getting the correct items from real steel

my confusion over vortec /pre vortec,I was told vortec had ballance shaft but it seems only v6 had ballance shaft

i'll be home next week but if you need dimentions/pictures sooner my wife can get them for you

if you want drop me a pm with your no & I'll ring you unfortunately you cant ring in as id need to use the vessels phone

ken
 
I can't tell you where to find them in the UK, as I am in Seattle, but I can tell you that you are best to either find the 906 heads or the comparable 12558062 head. These are both 96 and later vortec heads that are most commonly available. Other heads will fit, but you will encounter troubles, including a possible 30 HP loss, depending on which head you choose. Earlier, non-vortec heads require a different intake manifold, and you don't want to swim that river.
 
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