270L and you want large fish. Limiting. Do you want only a couple of fish then with character or something?
My choices:
Bichirs- you can put quite a few in there, they are predators and my favourite fish - stick to delhezis/senegals, don't go for ornate as it gets too big.
Nice cichlid: Really depends what you like i guess, I have a small jag cichlid cos they are bada$$ 8) A nice oscar is good, severum, uaru, festae, Green terror etc. Biggest baddest predatory cichlids here are the jaguar and the festae, oscar always wins on personality.
Fancy plecos: expensive, not really predators but certainly have an appeal, ask henward about the larger ones, he has a few now - btw they are poop machines = good filter needed.
Catfish: synodontis variants will harass bichirs, so tough mix, I am growing a pair of mystus cats right now and hope to add them to my community. Not too much choice but I highly reccomend the pictus cat, they are a tad expensive but are cool predatory catfishes.
Pink tailed chalceus: you could do a small group of these fellas, they are like jumbo predatory tetras.
Smaller varieties of eel: half-banded etc, need tank eel proofed, + larger cichlids will try to eat them, not very predatory but cool fish.
Thats pretty much it I guess... might have missed something.
My thoughts are go with a group of bichir (because they are easy to look after and super awesome) and grow out a few cichlids, sell the rest off and keep 1 that you really like.