Mark,
I have posted a request through your website to make part # 914 356 502 01 which is a white plastic clamp which pushes into the engine firewall and which secures the fuel lines on the firewall.
I have posted this thread as your website doesn't have the facility to accept an accompanying photo. PET lists this part as for '74 and up and 2 required per car.
With time the plastic becomes embrittled. I was trial fitting some ss fuel lines and pushed the lines into the clamp and sure enough, it snapped. The part is NLA as far as my searches show.
Hope you can help
DavidClick to view attachment