The results are scanned into PDF files, there are four races (Spring, Summer, Fall, Winter) per file so scroll down to see them all.  Except 1980 where two results are missing and 1978 the first year when they ran 7 times.

1989 MGP #48-51

1988 MGP #44-47

1987 MGP #40-43

1986 MGP #36-39

1985 MGP #32-35

1984 MGP #28-31

1983 MGP #24-27

1982 MGP #20-23

1981 MGP #16-19

1980 MGP #12-13 (Missing results for two race 14 & 15 Fall and Winter)

1979 MGP #8-11

1978 MGP #1-7