DD - what other differences do you think there are between GX and "A12T"? To my eye it's just a later version GX head.

The engine it comes off is mid dizzy A12 and had twin "SUs" (which I promptly sold a week after buying the engine as I was after the head. Got more for the carbs+inlet man than I paid for the whole lot. The guy who bought them was putting a Datsun A series into a 'Spridget' and wanted the engine to look vaguely 'British').

I have another GX head on my race-engine. Looks identical except it has the oil feed hole (as per early engines).

Quote:Right, Datsun 1200 GX engine was front distributor, so your engine was the A12T. Mid-distributor engine don't have the extra oil passage in the cylinder heads.

All these Datsun engines came with twin Hitachi sidedraught, hence the 'T' in A12T. SUs were not used. Hitachi design is probably a licensed version of the SU carburetor technology, or perhaps the patent expired. Anyways the Hitachis are very reliable so any bad things you hear about SUs don't apply.

A12T head was used by B210 and E10 (Cherry) and is similar to the A12 GX head. Similar ports sizes, same valves sizes, dual-valve springs. Ports may have a slightly different measurement. By contrast, the A14T has small ovals, same size as regular A14 head.

The A12T head appears to be every bit as good as the A12GX head, except you cannot just bolt it on an ealry engine. You can bolt the GX head on both old and new engines.

Thanks DD. Sounds like an 'A12T' Head is just a later model A12 'GX' Head (ie only difference being that it doesn't have the oil feed drilling).