I don't think you're going to reach 800 hp with unported Victor heads. Maybe ported Victor heads could get you there but I think you would need more than 12:1 compression. 800 hp will eat up the main webs in a factory block so you'll want to stockpile some cores or else go afternarket.

Talk to Dwayne at Porter Racing Heads and see what he has to say. He is pretty good a picking the cam and heads needed for a specific power goal.