I think that the engine in my 50 burb has been pulled. I am not sure if the engine that is in it now is the original. I am having trouble identifying whether or not it is still a 216 or a 235. I am not sure where the block casting number is located. I did remove the valve cover and found the head casting number--GM 3835517 with a 30 underneath that. Is there any place to look up head casting numbers to identify the ci of my engine. And will this tell me anything anyway? :confused: