Saving Old Seagulls

My son has been doing lost foam casting. And I've been doing 3d modeling. I wanted to see if he could cast a block and/or a tank.

So a bad one that I can take measurement off of is what I'm looking for.

Does anyone (in the US) have a DEFECTIVE Silver Century cylinder block that they would let go for cheap?

Also looking for a DEFECTIVE steel long range tank.