Wow, are you sure? I thought the lowest number gear set installed was in the 279 region? Something like that must've been used behind a two sp auto? Regardless, If you're now running a 4speed, gears like that will fry a clutch in short order. My 69 has m20 4speed and 3.23 gear set. I like them but even still I find myself searching for an extra gear when getting on the freeway. I run around 3100rpms at 70 mph.