small block heads, 4027596 casting # any good??

While the X head is the most sought after head for factory iron, in general, all small block heads flow about the same and will port out very similar to each other. I would not sweat what you have, there a good head.

Do note that the stealth porting above is designed to "Legally Cheat" and stepping up in a port job will bring better and bigger numbers over a broad area.

I would certainly use those heads. I seriously do not see a problem in having them ported and out flowing Edelbrock heads for less.