I did forget to mention a few things about the early-mid '80s A+ Metro head castings:
1. They do not have the fitting for the bypass hose to the water pump. My engine will be a full rebuild,so I just bought a water pump w/o bypass. Your situation may be different,so I thought you should be aware of the bypass issue.
2. These engines came with larger,1.4" intake valves from the factory,along with nicely cut throats into the port,below the valve. Exhaust valves were 1.15".
3. Supposedly the factory improved the ports a bit over earlier heads,since the Metro was in the market with other,more modern hatchbacks,and the factory was looking for more power. So,improved porting,larger intake valves,and the Metro cam(very similar to the 266 Kent) was the factory recipe. Comparing the Metro and Midget 12g1316 heads side by side,the difference in factory finishing of the ports is immediately obvious.
4. These are also 12G940 castings,but there are a few different heads out there with 12G940 casting numbers. This info is readily available online,and I'm trying to keep this short,so I'm not going to list them here. A couple minutes of research will spell it all out for you.
5. One quick way to spot the later heads is to look at the thermostat gasket area--the early heads are dead flat all the way across the rocker cover and thermostat gasket surfaces. The later heads have more of a gasket sealing "rail",running around the rocker area and thermostat. Bad description--if it doesn't make sense,let me know and I'll send a photo to you.
6. It does have the large valve guide bosses in the ports--especially on the exhaust side--intakes are a little better. Spend some time with a carbide burr to cut those bosses down,if you think you need to. All depends on what spec you're building your engine,and how you plan to use the car.
That's about it,and those are the reasons I went with this head for a reliable,every day driven Midget with a warm street engine. Buying the head through APT meant I got the casting I was looking for,unleaded seats,some combustion chamber work done,etc. I'm cleaning up the ports,blending in a few abrupt edges here and there,slimming down the guide bosses,etc,on my head,just to finish it off. New guides,valves,springs,and seats cut on a Serdi 100 machine and I should have a nice(unleaded) mild performance street head that will last. Fingers crossed,that is!
Finally,this head is a good fit for what I want out of my Midget;it may or may not be what you're looking for.I don't have or pretend to have the knowledge base of some of the guys on this forum. We're ****ed lucky to have Hap,Mike and some of the others on here as go-to guys when we have questions. They won't steer you wrong.
Jim