Keep in mind that I own (and love) 2 340 stroker A-body cars, but if I were wanting an (easy) 12 second car on the cheap (read - starting with a bare shell and no parts on the shelf yet), I'd go big block, and I'd choose the 400 for the extra room they offer. And for the cornering crowd, a 400 with aluminum heads and accessories isn't going to outweigh a small block by much if anything.