Mediocre build quality; the ports have many casting defects such as steps and sharp angles, which are not ideal. They are also quite large, resulting in the channels becoming funnel-shaped if someone tries to smooth them out.... Additionally, it does not accept a camshaft with a large lift, with R20 and the same company's valve springs, where the coil is 2.9mm thick, barely finishing, resulting in the little rooster and their pins, which were genuine, lighting up after 1000km during break-in and with relaxed driving... It was not a lubrication issue, as I also have a Takegawa oil pump with a higher flow rate.

I bought it two years ago and used it recently; I don't know if it has improved since then, but I certainly wouldn't take the risk of choosing it again... Get something else for the same money; there are others with better casting and fewer defects. To make a proper head, if it can be done... it requires work and additional cost...

In contrast, the non-magnetic steel valves included in the package are among the best I have seen.