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Crossflow alloy head casting numbers

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I forgot all about this till I got the head done recently which I have sat to the side for use with another block that I start next year. But some info about this head from two engine builders I spoke to. Both builders said that the cylinder head was machined that way to lower compression particular for turbo application. Both asked did the cylinder head come from a turbo xflow which it didn’t. They thought it unusual it to be done for normal application particular being c2 which is common and that there are type of cylinder heads available at the time if it was result of pinging due to head design.The work done to head was very good to the point it seems cast that way. One builder has only ever seen one head like that on a turbo the other said he never worked on one but heard of cylinder heads like it. Any truth in it-who knows. Unless the actual person who did the work is found for the reason for it done I will never know.Got a number of different cylinder heads and this one has a different story to it.
My belief is that it was to prevent pinging which were prone in unleaded XF and someone found it was good to use for turbo.


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There’s no chance this head came off a GEM reconditioned engine?

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There’s no chance this head came off a GEM reconditioned engine?


No didn’t it come off a GEM motor but not to say the cylinder head didn’t come from GEM factory either originally. The only history is came from mates ford xf s pack sedan which he pulled out for a v8 and placed xflow in a cortina till the cortina succumbed to rust. This is late 90’s early 2000’s. Other than that wouldn’t know.


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I just re read this thread from the beginning and Tony mentioned his came off a GEM engine, that is why I asked.
GEM did some weird stuff. A mate of mine has a 250 2v head he picked up at a swap meet. He dropped it off at the engine machinist to look over. He could tell it was a GEM engine when he stripped it down as they had their own valves, they are 5thou thicker at the base than the top where the collets are so they don’t have to worry about replacing, installing or k-lining the valve guides when they recondition the engine.

I wonder if they did something to the chamber to prevent a hot spot forming, I never heard of them casting their own heads or block, they tended to just use factory major components and recondition them their “special” way. Most fords 6 cylinders got a 60 thou overbore.

Did the bottom end have oversized pistons?

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Na the bottom original matching number etc etc. But I reckon the cylinder head is not original. That’s why I believe that was done for other reasons not for turbo. Just reckon it was a change over but mate never did it but do believe the original owner probably would’ve. Wouldn’t surprise that a lot of c2 heads were done like this from GEM. I don’t think it’s any special just a little more about it than all others. Just this one had a high hardness test. To me it kinda resembles attempt of a xe unmark head or E1.


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Except the chamber shape on the outside is like no other x flow head.  I don't believe gem would have anything to do with it as they wou,don't have HF cast into them.  My guess is it was a low production factory item to test something and they somehow made there way into a few production cars. 

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Except the chamber shape on the outside is like no other x flow head.  I don't believe gem would have anything to do with it as they wou,don't have HF cast into them.  My guess is it was a low production factory item to test something and they somehow made there way into a few production cars. 

Hmmm interesting. It does have hf9 cast into it. The only thing I can say about it is that it was machined very well. Anyway I like the look of it, had a little skimmed off and the ports look rather very clean compared to the others I have not sure it was from good casting or been cleaned up.


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I have an 84 efi XE and I'm interested to know what head I have as I'm not sure if its the original or not and there is no identification anywhere between 1st and second intake. I have search everywhere for a pic of c1 e2 ect.. but can't find one would be good if someone could post pics. Thanks.

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OK cool thanks but still seems strange that all XE  would just have one standard head for carb and efi and an Xf has multiple.
One reason for XF to have multiple is the change from leaded fuel to unleaded.

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3 hours ago, Mr Polson said:

One reason for XF to have multiple is the change from leaded fuel to unleaded.

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and XF went for many more years too, more time to get it right(supposedly)

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