My '67 Valiant 100 Big Block 4 Speed Restoration

Auto Metal Direct makes full floor pans for the a-body mopars.

You might want to PM user crackedback he might be able to locate a quarter panel for you out in california.

If you can swing the coin for some Schumaker tri-y headers that would be the hot ticket. They also make conversion motor mounts:

http://www.engine-swaps.com