Can somebody tell me a quick visual way to tell the difference between the "newer" eliminator AFR heads and the older castings? Thanks

 

There may be a better way than this, but you can look at the oil drainbacks at either end of the head. The older ones just had a small hole that was basically at the same level as the rest of the cast surface. The new ones have cast indentations around the hole which are supposed to eliminate the oil return problems the old ones had.
If you have a micrometer, you can also measure the valve stems (new ones are 8MM).

 

thank you sir