Ever see someone with a sagging engine bay wire harness?   Not only does it look bad, but it's dangerous too because those wires then sag down close to the turbocharger.  
 
You can try to fix it with a regular zip tie, but a regular zip tie doesn't have the special push/clip that secures the harness to the top of the firewall.   I looked for these for years before finally finding them.  Price is for 1.  Order as many as you need for your restoration projects.