A huge thanks to everyone for your help and in educating me! Especiall to Mopar who went above and beyond! It has been a real education since the orginal post of the value of the original engine to the matching car owner. I just wanted to give ya'll an update that I went to see the orginal engine today after many e-mails with the seller back and forth. The first thing I went to verify was the stamping number on the engine block. When the seller saw what I was trying to verify he told me that the previous owner had the engine rebuilt in 1978 and when they rebuilt the engine the stamping number with partial VIN was removed. I wish he would have let me know this in the many e-mails sent back and forth, but it does explain why he refused to send the pictures. All the other numbers I verified on the engine did match but after my education here and from Jerry MacNeish's book I understand that the stamping number iwth partial VIN is what proves it is a 68 Z-28. I did not bother to disassemble it to verify the crank. It also did not have the orginal air cleaner assembly, nor did he have every orginal nut and bolt as he claimed. He did have the muncie shifter, Rally wheels, clutch fan, and a few other small parts. All in all I did not see how he could be asking 12K without the correct stamping. I did not discuss the price with hiim just thanked him for his time and said I would be in touch. All in all I am so glad I found this forum and your exstesive knoweldge. Thanks again for all of your time and efforts, I truly appreciate it!!