X, J, or 308?

i have heard x or j will support 400 hp,but don't have any first hand info...

I've gone 11.22 @ 116 + weighing 3,540 lbs + with 1.88" intake 587 heads and .474" lift.
perfcar and others have as good or better numbers as well. I'm sure that's over 400hp, but you may get some widely varying #'s depending on which formula you use.