Cool, I fooled around with a custom Metro cam sprocket a long time ago but never really dialed it in.
The Miata was fitted with an adjustable cam sprocket a few years ago and after some fiddling it appeared to make a difference. Hopefully this experiment will confirm my original findings.
Locating an adjustable sprocket to fit the B3 engine was more or less an educated guess. Ironically sprockets for a 1.6 or 1.8 Miata engine will work.. of course the B3 only needs one sprocket instead of two. Buying the set allows me to put one on the Miata and one on the dyno.
I went with a set of el-cheapo ebay sprockets because ...well they were cheap. Better quality sprockets were available but the cheap ones were identical for intake and exhaust whereas the more expensive ones are different. The difference is limited to the silkscreen printed on the sprockets.
The red units are El-Cheapo sprockets of questionable quality. The blue sprocket is a better quality CorkSport... but I only had one.
Stay tuned!