I'm sure it is a genuine GX head, has no casting numbers, simply says 'NISSAN'. Has high oval ports, extra rocker oiling hole for early type A12, large water ports under inlet ports (blocked), 37mm and 29mm valves. A15 is 37mm and 30mm, A12GX are 35mm and 29mm.
Was originally on an A14 in a rally car, then a Lotus 7 replica (the guy i bought it off). I got the whole motor. He replaced it with a blacktop 4age but was disappointed that it was slower than with the a14.
He managed to cook it at some point (something to do with the radiator), and then said when he got the head skimmed it blew a head gasket again. Thats when i got it. Got a mate to get it checked out for me and turns out it wasn't straight. So I have just had it cleaned, straightened and a 5 thou skim. Also had pressure test, hardness test and crack test, these all came out fine.
Seats look fine but you might want to re lap them in. Ports are fairly large oval at 30x39mm (standard A15 is 28x34mm). Removed valve guide bosses etc. See the pictures.
Want $400 for it.
Also have some extractors/headers i'll sell. Pretty sure they are Coby's. The type you need sidedraughts to run with. Pretty rugged but will do the trick. Have a patch on them and lots of surface rust. Nothing some paint / heat wrap wont fix. SOLD
Sorry for shit phone camera photos.
