Even if someone weighed 50 lbs, no one should care about a 340x5 deadlift. People need to stop using bodyweight as an excuse for being weak.[/quote]
A person weighing 50 lbs and pulling 340x5 would be an impressive feat of strength. That’s a 6.8xBW pull for 5 reps. Lamar Gant pulled 5.2xBW for a single. Anyways the deadlift/BW ratio varies across weight classes so you should instead make a comparison to people in the same weight class.
The Elite Classification Standard can give you a feel for numbers across the powerlifting population. Using that, I would consider a 527@148 (3.6xBW) pull equally as impressive as a 697@275 (2.5xBW) pull, both international elite class. The main point is to compare yourself to others around your weight if you want to know how strong your are.