In preparation recently for attempting a repair of an early Ace engine block that threw a rod five decades ago, I had a local metallurgical firm do an analysis of the elemental composition of the block.
Below are the details of the alloy (element/%). Totals don't quite add due to rounding, I assume.
carbon/0
manganese/.31
phosphorous/0
tin/0.11
silicon/5.81
lead/0.15
nickel/0.38
chromium/0.03
copper/3.76
iron/0.98
aluminum/87.15
titanium/0.03
magnesium/0.12
zinc/1.40
Hope this helps anyone who may be working on a repair.