ISO 1967 Barracuda Service Manual
What you need is the
1967 Plymouth Factory Service Manual (FSM) which can be found used, or as a reprint, or on CD-ROM,
plus the
1967 Barracuda Supplement, because the Barracuda was a late year intro and didn't make the publishing date for the manual. The Supplement is freely circulating online in PDF form, but it's a large file. Here's a link:
Dropbox - 67 Barracuda Supplement Compressed.pdf