First order of business is to buy a 70 Plymouth Factory Service Manual and a 70-71 Factory Parts Book. Both are available on CD or paper. One advantage of the CD is that you can print out a page and if it gets torn or dirty you just print another.
If you still have questions, post them on Moparts. There are a lot of people here that will go out of their way to help out, if they think you are committed to your project.

Here are two book suppliers. They both sell on eBay and directly.

Bishko Book

Faxon Auto Literature