Although there are many different casting numbers, there is not a clearly bad choice among FE heads. The earlier heads have larger ports that work well in high RPM/high HP engines when ported, but the later heads have more modern combustion chamber design and high velocity/lower volume ports that work nicely for making torque. Those heads will work fine with a small cam and stock gears. You might get some additional power if they were lightly ported, but it's probably not worth the cost.
Make sure to invest in new valve springs if the rebuilder used the stock ones--the stock springs can break if you put a higher lift cam on them after they have lots of miles on them.
http://www.supermotors.net/vehicles/registry/9026
