The bog blocks used the same housing as all other 8 cylinder cars in 1968 except the 302. Group 1.153 (OUTLET, Cooling), P/N 3877660. HERE'S
a previous thread and a picture posted by JohnZ of the housing.
I believe the Alternator Bracket with the return spring tab is a 66 Chevelle (1st design) Big Block item. The 68 Camaro Big Block Bracket didn't have the tab.
Hope this helps...