I debated this same question last year. Ultimately, I went with Ray Barton and 540". The reason I didn't go any bigger was that I was building a mostly street driven car and even with 295 drag radials and Cal- Tracs, full throttle is possible only from a roll. And risky, even at that.

My 540 is mild; it idles at 850, has good street manners, runs fine on 91 pump swill (maybe even lower octane, I just haven't tried) and made 700hp on the engine dyno.

With today's new blocks and heads, there is no real down side to big cubic inches. But then, on the street, it is difficult if not impossible to use all the power that comes with those inches. And I won't go into the fact that these things can get down right scary on occasion.