stillnotavette

Ok I have acquired a 5.3 I think it is a lm7. My question is what kind of displacement can I get out of it. I would assume 30 over or even 60 over is doable but what is the max I could do. I have read a lot of different thing and am not sure what believe. I would assume 400+ cubic inchis not doable. what would be the max cubic inch's I could have.

Thanks