I did not mean to be naughty Ricardo, but I think you are mixing together weight limits from different years.
If we take the limit for cars intill 2000ccm it was (if I remember right) 880kg until 1988. Then the 920kg. Since 1992, I believe it was 960kg, for later rise to 1000kg. We are now talking about group A. The current Gr R has other weight limits.
A8 cars under 90s I think had to weigh 1230kg.