Recently, we purchased a relatively brand new high performance car engine to swap with our regular car engine for the purpose of gaining more horsepower. I need to find out the probability of corrosion of an aluminum alloy (possibly 319.0) part of a complete engine block brought to the shop that was not corroded prior to being brought to the shop... but, after two months of storage at the shop, these aluminum parts showed signs of corrosion. After an ordeal with the shop of over 2 months and upon pickup... these parts were corroded, apparently under normal storage conditions. Is it likely that this type of aluminum alloy can corrode in this amount of time? We have suspicion that the shop has been deceptive and the engine that we were returned in our car after services were rendered is not the engine that we brought to the shop to be swapped... because of this corrosion.