GM edicts in the 1960s

[442w30]

We've read a lot about the 400cid limit through 1969 and the no-racing ban from 1957/1963, but what about the 10llbs/hp rule?

I don't think I've ever read about where and when this came from.

Does anyone know?

I recently read that this was something starting around 1967, but I am not sure why other than to be for the same reason why GM got out of racing - to hedge itself against anti-trust scrutiny.

Thanks!