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I've posted a similar thread in the space marine section. There's a tournament at my local club, that allows no vehicles to be used, and your HQ must be 200 points or under.
I was thinking about taking marines, but you get through your points rather fast with them, then i thought about taking orks, i usually run speed freaks but without the allowance of armour i can take a Green tide list.
My current list is;
29 Ork boyz
29 Ork boyz
3 Power Klaws
Nobz don't really work on foot. I'd either use a smaller unit on bikes, or not use them at all.
The KFF is really iffy. Instead, I'd use a unit of 12-19 grots, to stand in front (giving your boyz a cover save), or sitting on an objective near your own deployment zone.
Also, you don't seem to have any long range shooting. How about some lootas, big guns, or shokk attakk guns? It's just a thought.
I'd be willing to bet good money, however, that the winner of the tournament is going to either be a list with a lot of monstrous creatures, or fast infantry, like assault marines or bike units. In other words, it'll probably be a list that has units that are similar to vehicles (in toughness or speed), but aren't vehicles.
"Any job worth doing, is worth doing with a powerklaw."