I have a stock 91 GT AOD with the factory option 327 rear gear . It is nice to cruise around town at 1200 rpms , but off the line it is a slug - I can only imagine what a 308 would feel like ... 25 years ago I had same year mustang and remember putting in 373 and it seemed a lot better - but still no rocket of the line . I heard the Ford motor gears seemed the least problematic of the brands , but the ratio I was thinking ( 390 ) not made by them . Do any of you guys with AODs run 410s and can offer some insight if it’s too much gear ? Would 373 gears be less stress on drivetrain parts and be best for a daily commuter or is it not really worth the hassle to go from 327 to 373 ?