I just managed to get my head of my a14 today, one of the head bolts snapped and jammed in the head 3 hours later and heaps of crc it was persuaded off. (although the bolt is still in the block).

Is it a gx head or has it been modeified if?
it has double valve springs, oval ports (these match up with the su manifold), on the bottom side in each valve group it looks like it has been recessed a couple of mm (i dont know if it is to allow for each piston), the head has the numbers h89 and 605 stamped on it. i have tried to find information on the head but it seams all gx head have nisan printed on them, mine does not and the numbers have thrown me off as well.

the pistons have a smooth concave dish in them is this standard? or will i be able to tell when i pull out the pistons.

You can write till your fingers drop off, but now that the head is off, how about a couple of pictures so that we can see what you are talking about. One of the port side of the head will be good.

If it has SU carbs, then these will not be original & this would suggest that perhaps it is not a GX head, but lets see what you have & a better assesment can be made. A good shot or two of the induction will be a help too.

As I had writen earlier this afternoon, there are three different GX heads that I know of.

Standard, & some GX pistons have the dish.

sorry they are hitachi carbies not su's i will try to copy a photo over