67 Barracuda with 383 and ECU… alternative engine harness options?

Maybe another '67 Barracuda harness.
Most of the difference in another '67 B will be wire length and whether the car was tach equipped.
It's not clear from the assembly drawings if there was a different harness for LA and B engined cars.
I'd check the parts book to be sure on that.

'68 is different enough that I would not go that route. You'ld have to move wires to their proper connector cavities and there may be other wiring differences but that would be the big thing. Also '68 tach wire goes through a grommet rather than make conenction in the bulkhead multiconnector.

Best bet might be to fix what you have, and then circle back to getting a replacement installed later.

For repair, depending on what is damaged, may need:
Open barrel crimpers and Chryser terminals, wire strippers. Sources for Chrysler type wire terminals
Splice connectors and shrink tubing. Inline wiring splice clips........from the Dodge RAM service manual
Deoxit and other cleaning supplies. What do y'all use to clean the metal connectors that go into the bulkhead on either side of the fw?
Adhesive free harness tape in couple widths. Vendor needed for cloth / fabric tape non adhesive type

The '67 service manual diagrams and the Assembly drawings (book from Faxon) will be helpful too. My review of Faxon book, 1967-1969 Dodge & Plymouth Body & Electrical Assembly Manual