AFAIK mechanically,the 68 to 70/71 model year 340s were all same short blocks (exc the one year only manual-trans cams, as you noted), and all had 2.02intake valve heads. Covers and such changed in 70, and intakes/carbs in 71. The 2.02s were dropped to 1.88 I think 72, Compression was dropped I think in 73 and those low-C engines had different guts.
Slow-typer again,lol.
