The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
Another significant advantage of Hulk (Worthy) is that he is more resistant to firearms than Hulk (Earth-2149). While Hulk (Earth-2149) can absorb energy to increase his strength and endurance, this has no effect on his vulnerability to firearms. This is a significant advantage for Hulk (Worthy) as he can use firearms to defeat Hulk (Earth-2149).
Finally, Hulk (Worthy) also has an advantage in fighting skill. While Hulk (Earth-2149) relies on his brute strength to fight, Hulk (Worthy) has Thunder's hammer fighting skills, which gives him a significant advantage.
For all these reasons, Hulk (Worthy) has a significant advantage over Hulk (Earth-2149) and therefore a good chance of winning the battle.