Well this is a fairly big job....first you will need motor mounts from a Big block C-body (69-72 should be the same). I have a nagging thought that the motor mount bosses on the 413 might be different then the later big blocks?

You will then need a Bigblock 727 tranny to replace the Smal block 727...the two are the same but bellhousing boltpatterns are different.

The motor home tranny probably has a short/stubby tailshaft so you will more then likely need to have the tailshaft swapped to have the proper mounting point for the tranny cross member.

You should be able to use the same drive shaft.

You will need a big block radiator and fan shroud as well as all the brackets and pullies to mount the power steering, alternator and A/C.

The kick down linkage from the motor home should work if it's the 3 piece, with 2 pivot points set-up. Your 72 fury with a big block would have originaly came with the single rod set-up used from 69 on up on the fusey C-bodies.

Exhaust manifolds and exhaust will be different as well. If you can find a good set of 68-72 C-body HP cast iron manifolds would be the best for all around reliability, performance and lower cost then headers. But the set of low flow log manifolds that are already on the motor should work as well.

Now the torsion bars might need upgrading, they will definetly need to be turned up to bring the front end up after the install, and a good front end alignment done.

The wiring in the engine compartment will need to be adjusted a bit since the coil and distributor are at the front of the motor on the 413.

I'm sure I forgot something but this should give you an idea of what is in store for you.

Happy C-body-ing...