the rear of the k member. i sat the 727 trans on the original trans crossmember and mount from the original /6 trans. that set the front to back position or the motor. then it was a case of lowering the motor in without a flexplate to see how much needed cutting from the 'k' and lowering again. from memory the 3rd cut was enough which just left the job of boxing in the 'k' for strength. i didn't have adapter mounts, i made my own. i found the wide fenderwell headers moved too much so i swapped the rubber mounts for solid ones, again i made them. i didn't notice much if any increase in vibration with the solid mounts either.