On 62's, the 250hp (base) and 300hp engines had a wide-ratio T-10 when a 4-speed was ordered, and there were no options; the 4-speed with the 340hp and 360hp engines was the close-ratio T-10 (again, no options).
The original '62 T-10's had a metal tag under the forward lower side cover bolt that indicated the gear ratios; wide-ratio boxes had "K" or "J-J" tags, and close-ratio boxes had "B-B", "C-C", "D-D", "J", or "LM" tags.
Other than the tags, there's no external way to determine the ratios; if you pull the side cover, the input shaft on a wide-ratio has 25 teeth, and it has 27 teeth on a close-ratio. If it's out of the car, see how many turns of the input shaft are required to get one full turn of the output shaft with the transmission in 1st gear - if it's 2-1/4 turns, it's a close-ratio, if it's 2-1/2 turns, it's a wide-ratio.
Wally
