Yes, the head is drilled and tapped for both bolt patterns, but the old hole is not fitted with a stud. H74 head (1976-1978 A12) uses the new type bolt pattern gasket.


There were several heads used for A12-powered B210. For Japan market:

old bolt pattern
* 11041-H5002 HEAD ASSY-cylinder A12S
* 11041-M3000 HEAD ASSY-CYLINDER A12S V 7510-7612
* 11041-M3001 HEAD ASSY-CYLINDER A12S V 7701-

new bolt pattern
* 11041-H7401 HEAD ASSY-CYLINDER A12S S,K -7612
* 11041-H7403 HEAD ASSY-CYLINDER A12S S,K 7701-

I think I have attached the correct photo this time? I have pulled apart plenty of 120y motors before without finding a head like this. And no it is not ported at all. I think it could be a gx head of some sort?

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All GX heads have extra large oval ports, water holes below the ports, and closed chambers.

The one here is an open chamber head (the opposite of a heart-shaped combustion chamber). As far as I know, open chamber was not used for the 120Y. So what did you want to know? It's not a performance head, it's a smog head. Will work OK for a 1200cc engine, but prone to run-on (dieseling) unless the carburetor is carefully adjusted.

Being an Open chamber - lower compression ? - possibly could use it for a turbo application ?

It is same compression as a regular head.
* A-series varies compression by CC of piston dish
* L-series varies compression by CC of combustion chamber (and dish)

The open chamber gets rid of quench. Quench causes temps to spike and thus more oxides of nitrogen (NOx).

Quote:

Simple question from gg-datsun.And im also interested in finding out also..

So What head is this??

Based on the info we've got so far, it could be a 1974 A13 head:
* Only head known to have 28x30 mm intake ports
* A rare piece, only sold in USA for one year

GG-DATSUN, what are the exact measurement of the intake ports?

Yeah dd just measured them mate, they are 28x30 as you said.

It's a good head for an A12.

Was 75 hp ouput without having to rev higher than stock.

How would it perform up against the likes of a H89 head? on an a12...