You didn't mention which trans you have.Don't forget the bearing retainer size.The late 3 speed will have a larger one as opposed to an early (before 68-9?)4 spd trans.You can change that to match with the correct(same front bearing different retainer) trans.The all syncro 3 spd for a BB (stock in 70 up Roadrunner and more) has the large bolt pattern same as a 4 spd.I don't think they used the smaller A-250 trans that late with V-8, maybe in a six.