165s were turned out from 1964 to 1975. Check the serial number to determine when a specific unit was manufactured.
http://www.tractordata.com/farm-tractors/000/7/4/746-massey-ferguson-165.html
What year is a massey ferguson 165 with a serial number of 37786240?
1973
The Massey Ferguson 165 tractor with the serial number 9A47957 was manufactured in 1970. Massey Ferguson tractors typically have serial numbers that can be decoded to determine their production year, and the "9A" prefix indicates it was built in that year.
1974 http://www.tractordata.com/farm-tractors/000/7/4/746-massey-ferguson-165.html
1974
1971
A Massey Ferguson 165 with a serial number of 9A 96068 was produced in 1971. The "9A" prefix indicates it was manufactured in that year, as Massey Ferguson used specific serial number prefixes to identify the production year of their tractors.
that would be 1968
1973
a 165 Massey-ferguson oil pan holds 8 1/2 quarts
The Massey Ferguson 165 with the serial number 9A 134935 was manufactured in 1970. The serial number indicates that it falls within the production range for that model year, which was produced from 1968 to 1975.
in the oil filler hole