Just an update on this forum I posted a few weeks ago.
I went this morning to the place that sells Japenese imported engines.
We found two A15 engines.
Unfortunately it was too dark inside the place to see the number casted ontop of the head to compair to the technical information on this site.
I did however remember all the stuff that I read on the technical page and found the following:

Due to it being to bad lighted to see inside the ports, I used my finger to feel if there is any obstruction inside all the intake ports.
No obstructions were found.
I could only feel the valve guides and valves.
They were oval port with water jackets.
When looking to the combustion chamber, it also has a heart shaped chamber like the pictures of the GX heads in the tech section.
Possibly 10:1 comp.
What do you guys think.
Is it a good buy?
The price was not too much.

If you were at a nightclub, looking to pickup a girl, the place is full of blokes, and the only girl in the club (and she's very attractive), what if she came up to you, and said "how about it big boy...for a night you'll remember forever, All I ask for is breakfast..."

What do you do?

ps ..it's not some seedy gay bar...

pps. Actually I know nothing about gay bars.

If she said that to me, i would look around franticly for her guide dog.

1200GXman
Go back & have another look. This time, take a lantern type torch with you & make sure it has a nice fresh battery in it. You will be much better informed when you get to see it properly.

Another update on this thread.

I went there again.
The number on the head is H89.
I looked in the technical section but there is no information on this head.
Will this head work on a A12 engine block?
And is it a good head for performance?

Unknown. But H89 has been talked about, use the search button on the left.

I agree with what Feral says,about milling the cyl head, I read in Dess Hammill"s book about 4 cylinder engine blueprinting,about it being better to weld up/add material to the compression chamber than to mill the cyl head surface. By decreasing the capacity of the combustion chamber you add compression, without taking any surface. No issues with push rods, timming, direct to the point, clearances.Also, the compression can be tuned in, because if too much compression is gotten, or, instead, more compression is needed, material could be shaved away from chamber or else added to it. That would be imposible to do on the full cylinder head surface.In other words, compression can be restored to original ratios, or modified, choice only welding offers. No way back on the other method.
Later_______________________

Is there an ideal spot in the chamber to add the aluminum?

Flattening the bottom (if you're looking down at the head) of the dish?

Hey Yup
I've got a couple of H89 A15 heads on the shelf, they're a good head, oval port and heart shaped chambers.
A huge improvement over any round port head, and they're not the nasty 'emmision control' head either....
You can fit the bigger valves in em no problem. The double valve springs are probably still available from Nissan.

I cant remember exactly how much to mill the things for an A12, but it's not a huge amount if you're going to use flat top pistons and a 120 thou overbore to get it bang on 1300cc...

had a look at my a15, oval port and round chambers, H89I then has 618 as cast number.
It has bugger all emisions on it but can any one shed light on it?