Geez, are you really going to make 550+ HP with a stroker? I am guessing if the answer is yes, this will not be a street machine.
I would think that with any small block you would want the outside bolts away from the main webbing. Splayed caps fasten more from the cylinder webbing. Its my understanding that this is the prefered way of beefing up a SBC bottom end.
I am no expert by any means, just my thoughts.