Early LA motor compared to Later LA motor?

Water pump and timing covers changed in 70. Induction hardened valve seats in 72. Electronic ignition phased in 72-74. Steel cranks in 318-340 phased in after 71. Compression down on 340 in 72. 340 & 360 heads same in 72. 318 compression varied slightly but trended downward after 70 (nominally 8.5). Various emission control hardware added, especially from 72 on.