It obviously has oval ports but i tried figuring it out with no luck. i cc the cambers and it has 29cc. i remember measuring the exhaust valves at 30mm but intake was 35 or 37. I think. this must be a gx head or a nissan comp head?

Congratulations,you are the owner of a GENUINE GX head.
The "Nissan" cast into the top is the give away.
Cheers

Looks like it never be'n shaved Iether! verry nice.

That is a Competition Head/A12T head. For a 1974-up engine, because it is missing the oil passage. GX head has a the oil passage on the face.



Head ID

I thought it could of be'n that head But I had forgoten what the difference was?

OK a post 74 GX head as opposed to the garden variety oval port head.

thanks.

Not a GX head. It is JDM A12T head, which were sold in USA by Datsun Competition. It is almost identical to a GX head.

Garden variety oval port head is your typical A14/A15 head. The A12T head has much bigger ports than any A14 head.

DD,i'm not disputing your correct terminology/description,but here in Oz these heads where sold by(fact)my sponsor at the time a Melbourne Nissan/Datsun dealer also they where the official Australian arm of the then Datsun Racing Team and where marketed as GX heads(for competition)i owned two of them.
Yes they are a totally differant casting,just as the 510 FIA head was a totally differant casting only one of which i owned during my early motor sport days and used on a bored and stroked L16.

Hope this clears up the Oz connection.

Cheers

Agreed. Datsun Competition marketed them as GX heads too.