My 72 350 base engine has what appears to be two different heads. The markings on the front are different on each of them. One looks to be step with a piramid on it, the other one has two steps on it with a piramid on it. The engine does not show any signs of ever being apart. Is this a normal thing or did they run out of one head and put another one  on?  I have seen many of these small block cars and all have the same design on the front of the head.  The design on mine are off to the side and not in the middle as some I have seen.  What do I have here?  THANKS   Mark

It's possible it was assembled that way, but it's not really common. Just because the heads have the same casting identifiers(camel humps, housetops, etc) doesn't mean they have the same valve diameters, or combustion chamber volume. By the same token, heads with different casting identifiers could have the exact same valve diameters, and combustion chambers.
The only way to determine what heads you have is by the casting numbers. You'll need to pull the valve covers to see them, usually, tho sometimes one is visible thru the oil filler hole in the valve cover. You also need to check the casting dates on the heads to see if they are compatible with the assembly date of the engine.
Casting numbers will usually tell the tale. However.....it's always possible that someone has changed the valve diameter on small valve heads to the larger diameter valves, rendering the casting IDs useless.
Check the casting #s and dates, and let us know what you find. We can decipher them from there.
Adams' Apple2010-02-22 21:02:32

 THANKS again Joel,  I will look at the heads.  Mark

O.K., Here goes. Both heads have GM stamped/embossed in them. One has a 7 next to GM, the other has a 24 next to GM. The casting numbers appear to be the same. #3873487X  The second "3" could possibly be a "8", not sure. The date is very prominate on one, B-72. The other is less ledgeable. LOOKS to be B-62.  Hope this helps. Identifiers seem to be different.  Both have square bases, but one has only a house top point, the other has another step and a house top.  ?????  THANKS   Mark

I'll bet the number is actually 3973487X which would be 71-72 350, 75 cc  w/ larger valves.  Check your second digit. 

 You are probably correct sundevil on the "9". I looked at that but could not decifer the stamp. So are these heads higher cc or larger valves or both?  Are they a better, hotter head? What do I have?  THANKS      That list is extensive and VERY useful.   Mark

3973487....71-72...350..........1.94/1.5 or 2.02/1.6 valves, was also used on '71 350/330hp LT1, 75cc chamber
3973487X...71-72...350..........1.94/1.5 or 2.02/1.6 valves, 75cc chamber

For Corvette application, the 3873487 head was used on the 200 & 255 HP engines.
If you add the "X" to the casting #, then it was only used for the later production '72, 200 hp(base engine), AND the LT1.
Date-wise, you have a B-72, which is:
B = February
7= 7th
2- '72

The B62 would decipher the same....Feb 6th, '72.
So...if your engine was assembled on, or after Feb. 7th of '72, then these are prolly the original heads. Since it is a 200 hp engine, they prolly also have the 1.94/1.5 valves. Just your basic, small valve, small-block heads.

 THANKS a BUNCH to all who added thoughts.  I am happy that it is a good engine and can be up graded to a degree.   preciate it.   manchestershark2010-02-24 08:30:10