Slant six head numbers

pishta said
In 273 speak, the letter was the year after introduction, ie A was 65, B was 66 etc. If the 225 followed suit, G would be 67. I'm probably way off.

R: 1961
S: 1962
T: 1963
V: 1964
A: 1965
B: 1966
C: 1967
D: 1968
E: 1969
F: 1970
G: 1971
H: 1972
J: 1973
(…)