I'm not really as familiar with the 59A style of bottom end, but this seems pretty beefy compared to my recollections. It's a little off the subject of the bottom end, but I wish you could stick your fingers in those end exhaust ports. They are so smooth and the corners nice and rounded. Instead of having flat thin walls just before they dump out, these blocks have smooth flowing thick corners and no little wires left over from casting.
The center main bearing cap is HUGE! I can't imagine needing additional support except for the most extreme competition engines. There was also a general consensus from the flatheaders that were gathered around like vultures to a ripe, juicy carcass, that the main bearing webs seemed stouter as well. I couldn't tell, but I'll take their word for it at this point.