Xscream was the first to use them i think, then TPE and now ET. They are snowmobile reeds, can remember wich sled.
They use a custom made spacer, mill off the mounting bracket/ears on the reed housing, and stuff it in the spacer.
Big reeds were used in the early 2000's. I ran an adapter set on my race boat in 02. I am not quite sure who used it originally but it's no big invention other than
if you use the AC1000 cages the case reeds blocks have a very good chance of cracking. I would only build that setup for those who understand the
risks of what comes with it.