the only real site that has updated marvel info is Marvel.com, and this is how the strength levels go:
Level 1 means Normal Strength or peak human strength
Level 2 means 1-2 tons
Level 3 means 2-10 tons
Level 4 means 10-25 tons
Level 5 means 25-80 tons
Level 6 means 80- Low Level Class 100
Level 7 means Class 100