Aftermarket shoulder belts for 68 barracuda convertible

I agree shoulder belts are a good feature BUT engineered incorrectly COULD cause more harm than benefit.

As to a chain...

Make a seat belt with a female clasp at both ends

Plug the rear end into the short male part for the rear seat.

Add another short male section to the stock location of the front seat

Plug the front end of this new belt into it.

Seat belt that can be removed!