There are a wide varity of the old packs, some willl accomidate 80s and some will not. There are several versions of that USD one, at that angle I can't tell which it is. Some will only accomidate 72s, some will handle both 72s and 80s but are a pain to swap tanks (you must loosen/tighten 2 wing nuts) and there is another version that has a lever latch what will accomidate both tanks and is easy to swap tank.
There is a way to easily modify most of those that will not accomidate 80s so an 80 will fit. If it uses 2 wing nuts or regular nuts (like those USD ones do)_you can extend the threaded sections buy installing 1 inch threaded standoffs ($4 each at McMaster) on the tank side of the plate. I also like a washer under the standoff to spread out the load.
Many of those (including that model of USD) thicker plastic plates are fine for single hose regs but if you intend to use it with a double hose reg, a lot of them do lot allow the reg to be placed as low as it should and the extra distance it holds the tank from the body is not ideal. Those USD plates can not be lowered as much as needed due to the way the Drings are placed on the harness (unless you reharness the BP). For a DH reg, the thin, single layer plates are much better. Most of those can be modified with the stand offs as well.
