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

Thanks guys, I can’t get a top view of the head or it would be easy to work it out. I didn’t think it was an A12 head as I can’t find any pics on tech wiki that match the stud pattern on the inlet and exhaust which is what had me stumped.

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

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

Hi all,

Need some help to identify this head I’m looking to buy.

I don’t have any other pics and I’m not sure which head it is.

Cheers
Matt

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