honda RSC Racing Service Center history?

[lostideas]

Any of long time Honda guys know anything about honda Racing Service Center (RSC)? I seen it pop up here and there on searches but nothing that really talks about what it was to the car line. The info focuses manly on the Bikes. Reason I ask is I picked up A NOS RSC timing chain tensioner and it came with a RSC N500 engine service manual dated 1973.12.20 , bad thing is that its all in Japanese but looks like it could be interesting as the hand drawn pictures look to be showing where to port the intake port, How to adjust the manual tensioner ,and how to set timing and also has huge list of parts with a check list next to each part? it does make mention of n600 in a few places with a few random part numbers. any info would be appreciated thanks