Re: 1957 ford ranchero
Not sure about the T5. I've got a '58 with an '89 5.0(carbed for now) and an AOD. I switched over to an earlier style front sump pan, oil pump pickup, and timing cover. The timing pointer was a little tricky.
I used motor mounts for a '67 cougar, I drilled holes through the centers of the mounts and enlarged the holes in the stock crossmember to run bolts through. I cut the rear tangs off of the motor mounts on each side.
I've also seen horizontal tubes welded into the crossmember and the same mounts used in the stock fashion. If I did it again I would have drilled the holes differently so as to move the motor back further, clearance to the radiator is a little tight.
For the trans crossmember I used the '58 ends that bolt to the frame and fabricated a new center section that stepped backwards to line up with the AOD trans mount.
I hope this helps, let me know if you have further questions.