Somewhere stamped on the Carrier you will find the Identification Code. Example, a 1967 C20 with 4.11 ratio would be stamped "HW". Note these codes were not always the same year after year, so get the code and report back so we can help figure out what you have.
The 4.11 ratio would have a tooth count of 37-9 (stamped on the ring gear)...37 divided by 9 = 4.11.
Mike B
