Let's not all jump to conclusions here....
Let's break this down a bit...
POWER:Kang has no superhuman abilities, but courtesy of 40th century technology has mastered combat and tactics.
VERDICT:Okay, this would not help him against Galactus at all...
Kang = 0 , Galactus = 1
POWER:Kang is thoroughly versed in the principles of time travel.
VERDICT:
I see this giving him a means of escape against Galactus, should he need it. OR he could go back in time and kill Galactus' mom.
Kang = 1 , Galactus = 1
POWER:Kang wears highly advanced battle armor that enhances his strength; is capable of energy, hologram and force-field projection and the ability to control other forms of technology.
VERDICT:
If Annihilus and Thanos can team up to take down Galactus....I think (if written correctly) Kang could too! The key here would be "control other forms of Technology". Couldn't he manipulate Galactus' machinery that converts a planets essence into energy and give Galactus "food poisonig" so to speak?
Kang = 2 , Galactus = 1
POWER:
Via his "time-ship", Kang has access to technology from any century.
VERDICT: Do we even know if Galactus is around in the 40th century? Maybe in the 38th century someone creates a "Galactus-Gun" that Kang can bring to 2008 and do Galactus in???
Kang = 3 , Galactus = 1
seems to me that KANG is sitting pretty!
(Vaultman made me do this, I swear he did!)