As previous posters have said this is a big undertaking.
I looked at doing this myself a while back, thinking it should just be a bolt in with the only major surgery being the cutting of the drive shaft.
A quick measurement with a tape measure cured me of that idea. As others have pointed out, lots and lots of metal cutting.
The GM conversion is by Kiesler (hope spelling is right), and theirs is litterly a bolt in job. No metal work at all, other than on the passenger side where the firewall and floor meet at the pinchweld. A hammer cures this problem very quickly.
What they use is the late GM Model GM4L60E (4speed), and I understand now that there is a kit for the 4L65E (5 speed), that has a removeable bellhousing. The company makes bellhousings so no matter what engine you've got, they have the proper bell housing for your application. The kit comes complete with: transmission, converter, flex plate, mounts, crossmember, drive shaft, electronic controller (trans is computer controlled type), and everything else you'll need. It's not an inexpensive kit, but it sure beats the altenative using the A500, which by the way is the 904 transmission, with the overdrive unit on back. If you insist on using the Mopar overdrive transmission, then I would look at the A518, which is the 727 with the overdrive unit. The overdrive units by the way are the same unit on both transmission types.
Your other option of course is the Gear Venders overdrive unit.
transman