The casting numbers on the cylinder heads, will only tell you what the cylinder heads are from. The number on the block, behind the drivers side cylinder head will tell you what your engine is from.
I like this list for cylinder heads
http://www.nastyz28.com/sbchevy/sbch.php
This is where the engine id is found
http://speednik.com/files/2013/09/chevyasylum-com.jpg