As mentioned above pay close attention to gear ratios . The common swap back in the day was 5 speed from 5.0 mustang. If you use one with these ratios you need to go down in rear gear 3.00 3.55 max. If you run 3.89 1st and 2nd gear are pretty much useless . (5.0 mustangs came with 3.08 rears in the 80 s and 90s )



