It looks like the Pierce castings head. They've been around for a good few years now, there were a few companies selling them at one point, including MED.
MED used to sell theirs as modified versions featuring improved porting and larger valve sizes, though they don't seem to list them on the website any more.
As standard they require some "finishing" and the small inlet may limit power, depending on your application ? What's your engine spec and intended use ?
Well, my engine at the moment is a standard metro 1275, but the plan is to bore it to 1310cc, Swiftune SW5 cam, 7 port head (twin Weber 45DCOE), balanced crank, lightened flywheel, straight cut box, LSD and ARP head studs.
I was hoping for around 100hp, but keeping it fairly reliable but still fairly quick. I did notice the smaller valves so if needed I will increase the valve size.
I assume if MED used to sell it, it should pretty good?