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Head Identifcation
Not too shy to talk
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From Central Coast NSW
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Hi all,

Need some help to identify this head Iím looking to buy.

I donít have any other pics and Iím not sure which head it is.

Cheers
Matt

Attach file:



jpg  IMG_3172.jpg (34.67 KB)
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jpg  IMG_3169.jpg (42.71 KB)
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jpg  IMG_3170.jpg (40.91 KB)
18284_5c6121dfcf5d3.jpg 320X240 px

jpg  IMG_3173.jpg (35.67 KB)
18284_5c6121f0ad4aa.jpg 320X240 px

jpg  IMG_3171.jpg (42.79 KB)
18284_5c6121fae1f0b.jpg 320X240 px

Posted on: 2/11 6:56

Edited by Sherodat on 2019/2/11 7:12:00
Edited by Sherodat on 2019/2/11 7:19:26
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Re: Head Identifcation
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Here's my guess

Looks to me like an newer A12 (120Y) round-port head ground out to oval shape

Larger valves fitted, but the seats are not a 3-angle valve job like the original Datsun machining (which helps flow at lower speeds). Notched for larger valves too, so if you put it in an A12, maybe should notch the cylinder bores too. Might be a nice head for running over 4000 RPM frequently. Below that probably make less power than a stock head

Won't fit a 1200 engine unless modified for the oil passage. Will fit 120Y engines or A14/A15 engines

Posted on: 2/11 10:11
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Re: Head Identifcation
No life (a.k.a. DattoMaster)
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Looks like a H75, mill them and you get a high comp H89
Ports look like they had some work to them definitely not stock cast

Posted on: 2/11 11:53
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Re: Head Identifcation
Not too shy to talk
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Thanks guys, I canít get a top view of the head or it would be easy to work it out. I didnít think it was an A12 head as I canít find any pics on tech wiki that match the stud pattern on the inlet and exhaust which is what had me stumped.

Posted on: 2/11 12:50
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Re: Head Identifcation
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It's a puzzler. They only ones I could find similar are G25 and H74 although our photos have only the new bolt pattern, reportedly some G25 have both bolt patterns (like in your photo here)

More curiously is the spark plug details ... I don't recall seeing any like that

Regardless whether it is A12 or A14 makes little difference. Some A14 is round-port, and some A12 is larger oval-port than A14 oval-port. The compression is the same, but only some of the newest heads are lower compression (e.g. 1981-up A15 heads) everything else is 29-31cc

Posted on: 2/11 19:52
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Re: Head Identifcation
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I was looking at the photos of heads with/out water holes below the intake ports. And with "hump" shape of casting instead of "triangle" shape

Attach file:



jpg  Sherodat IMG_3172 right side up.jpg (29.50 KB)
174_5c627b8d537b5.jpg 500X375 px

jpg  intake face Hump shape VS triangle shape.jpg (33.71 KB)
174_5c627bc916d9c.jpg 500X300 px

Posted on: 2/12 7:54
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Re: Head Identifcation
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It seems that only Round-port heads have those shapes

this is the only one with Hump-shape on intake face. But then we don't have photos of every head type ... The 728 may be similar but no photo
G25 from B120 1979-1989
Open in new window

Posted on: 2/12 8:16
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Re: Head Identifcation
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It seems that only Round-port heads have those shapes

this is the only one with Hump-shape on intake face. But then we don't have photos of every head type ... The 728 may be similar but no photo
G25 from B120 1979-1989
Open in new window

Posted on: 2/12 8:16
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Re: Head Identifcation
Not too shy to talk
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Thanks for the follow up. It makes sense it's a round port head with port work to make them oval shaped. One other question, all the A12 head pics appear to have rounded edges etc where as this head appears to have straighter edges? Don't know if that makes any difference to the type of head it could be.

Attach file:



jpg  Head ID.jpg (119.11 KB)
18284_5c62874c0b37d.jpg 640X480 px

Posted on: 2/12 8:44
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Re: Head Identifcation
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I don't see any clear difference there. Do you have a photo of a round-ish one?

Posted on: 2/12 9:19
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