A scratch blocks with triple web were cast 7B-7E. Prior dated 428 castings are single web A scratch and castings dated after were C scratch continuing with triple web.
The Craigslist block is pre reinforced crank saddle (triple web)
Kerry
What are you calling "triple web reinforcing"? This is my A block. 7E31.
It was just the current evolution of 428 blocks at that point. The cast in gussets have nothing to do with reinforcing the mains. They are supports for the pan rails.
You would need to tie those to the main caps like 427 blocks have to have any effect and that isn't terribly significant at all. A girdle tying that all together is a different story.