This oring is tough to find when you need it. They fit the port in the picture at the green arrows. These ports are for the capillary line or oil bleed lines from the expansion valve and evaporator core.
REBUILT 73-76 GM A/C R12 VIR VALVE Air Conditioning Expansion POA AC Camaro
66-73 15-51 A/C POA ELIMINATOR UPGRADE VALVE Air Conditioning AC Camaro GTO 442
66-73 15-52 A/C POA UPDATE ELIMINATOR VALVE Air Conditioning AC 15-52 5910594
66-73 GM BILLET 15-51 A/C POA ELIMINATOR UPGRADE VALVE Air Conditioning AC
POA Update Kit (134A) 1965-73 GM/Ford Applications [50-2551A]
POA Update Kit (134A) 1965-73 GM/Ford Applications [50-2552A]
![POA Update Kit (134A) 1965-73 GM/Ford Applications [50-2551A]](https://images.buynet.work/thumb.php?i=396646773&s=240)
![POA Update Kit (134A) 1965-73 GM/Ford Applications [50-2552A]](https://images.buynet.work/thumb.php?i=396646825&s=240)