Originally Posted by Nolimitslja
See that's what I'm curious about I'm wondering if you can drop the rear end from the mustang and just with a couple bolts bolt it up to the read end of the probe and then the engine should be easy because the fact the frame is big enough to support a 6 in there sideways it shouldn't be too hard to get a 8 in their straight..... Plus I found a 357 windsor in a focus so I know you can fit a 8 in a probe

For $5500 you can purchase the pieces to a kit (minus motor, trans, and rearend) to bolt a RWD V8 into a Focus.
No one makes a kit for the Probe so you are looking at TONS of custom fabrication work. Anything can be done though, all it take is money.