My 1979 International 1723 gas school bus weight is 21,700 lbs. The 1980 should be very similar. I wouldn't think Gas v/s Diesel would change the weight that much.
International School of Beijing was created in 1980.
Florida International University School of Architecture was created in 1980.
Busan International High School was created in 1997.
1980 (depending on your weight)
STI International was created in 1980.
LMS International was created in 1980.
Liberty International was created in 1980.
DEP International was created in 1980.
Drak Pack - 1980 International Graffiti 1-3 was released on: USA: 20 September 1980
Just Detention International was created in 1980.
International Trade Administration was created in 1980.
International Decision Systems was created in 1980.