Use the pan and pickup from the old (64) engine. Also be aware the hole in the end of the crank is larger in the 1970 engine and will require the 68 and later flexplate, and an adapter bushing, if using the 64 auto trans. If using a standard shift trans, you will need a 68 up flywheel, and a pilot bearing from a late '90's Dakota.
PS: I have the adapter bushings available. PM if you need one.