Heres a gear chart from brewers performance In regards to tire diameter, and final drive ratio to determine speedometer gear. If you have a 225 60 R15 which is a 15" tall tire,
((( however i cannot decipher what you have tirewise in your post. Is it a 50, 60, 70 series?)))
and a 3.91 rear gear it says 41T
View attachment 1715600342