I havent played Epic since this version but am currently expanding some of my forces and would like to know where i can find stats for some of the things missing from the armies book like Knights, mechboy gargants, Gorgons ect.
Thanks.

Those stats can be found in the Firepower supplements that GW brought out in support of 3rd Edition.

Adeptus Mechanicus Detachments are in Firepower #1, the stats for Knights are: Speed 25cm, Range 45 cm, Firepower 2, Assault 4, Armour 5, Special Ability-save. Costs 28 points.

Gorgons are also found in Firepower #1, as transports for Adeptus Arbites, in the article 'Warriors of Justice'. The stats for Gorgons are: Speed 25cm, Range 30cm, Firepower (disrupt), Assault 1, Armour 5, Special Ability-Transport(2). Obviously these stats are for the smaller Gorgon design found in early Epic not the Forgeworld Gorgon. Costs 14 points.

If your interested in the supplements, the Firepowers are much more useful than the Epic Magazines, with Firepower 1 being probably the best. They come up on Ebay pretty regular. I believe a PDF of Firepower 1 is on Scribd.

I'll have to look for the Mekboy Gargant stats, I think I saw some once (or at least a reference).

Thanks thats a good start.