My son bought a org. (looking) 74 z. Every thang seems to factory except the heads. The heads do have the 2.02 valves + guide plats, part #330545,400 tranny ? But if i am reading the date code and the part number right, and look up on this site , they would be a 72 or maybe an early 73- Z head ?? Right,? is there any way they could have been put on a 74 Z at the factory?? The stamp code at passanger side by front of head is CLK =73-74 block. This site has the head 330545 as a 305 head ,but others say it had the 2.02 valves and guids,for corvet and camaro Z cars. thanks for any thought .