easiest would be to take a 440 steel crank & turn the counterweights down to 7.25 then turn the mains down to the smaller 400 journal size after mocking up with new std main bearings & use the KB stroker pistons for this combo, gives 451 cubes. Not sure if the rods have to be changed if you offset grind the rod journals down to 2.20 or if they make a special rod bearing for that but that gives you 470 cubes & either one gives faster revving more cubes in the lighter/narrower 400 block. EDIT on second thought it would not be faster revving than a 440 cuz you would be useing the 440 stroke (I was thinking 400 stroke).