Aluminium Recovery from Engine Blocks.

Generally speaking, by weight what percentage of Aluminium alloy and steel is there in 'Aluminium Alloy Engine Blocks'? I am planning to buy scrap engine blocks but I am not sure what percentage of aluminium alloy and other metals will be recovered from it once i dismantle it completely. Can anyone help.

Shredders price their buying at 40-45% aluminum recovery for engine blocks. With enough random volume you should end up around there too but any individual block can be much lower or higher.