Sound Deadener

If you did the whole thing and Dynamat I'd say about 4 to 4 1/2 sqr yards going from the front floor kick back all the way under the rear deck, then put the stock back board back up behind seat..and install an under hood style mat and have it clip to the x frame behind seat/truck side. You can cut them to the smaller size needed and they insulate well obviously. Chy 300's have'm