First off, i went with a magnum core for my deal because there are plenty of cheap core motors out there. If you plan on running a 600 hp stock block for a long time that is worth considering. Since the deck height is so tall i would look for a stroker combo that uses the longest stroke commonly available and the longest reasonably priced h beam rods, all to make a big yet light rotating assembly. The more cubes, could equal lighter pistons and less rpm combined with more torque at lower rpm. I don't know if a 4.25 crank is available but would be great to have 430+ cubes.
I did find a 6.125 long hbeam rod on Molners web site .SBC with 2.00 rod bearing. That would allow another .115 stroke on any 2.123(mopar rod size) crank.