I have noticed a ton of people on here wanting info on these engines. My question is this; I know they are all 350s after 1970 and only 302s and 4 bolt 350s were made using it in 1969. But the data I have found indicates these blocks left production in 1975. But I keep reading they were produced through 1979. This seems odd to me since all of my info is from GM documentation accrued by other sources. Where did this 1979 info come from? I currently own one of these blocks and have seen several others (the most common of block castings) and I have never seen one with a date later than 1975.