I'd get a truck engine. I had no problem finding one out of a wrecked truck. There are lots of them. I paid 1300 for the one i have now only 41k on it.

 

That sounds like a nice one

Usually the police engines consist of a allot of idle hours. It's been posted, these extended idle hours can clog them up and oil change regimens are stretched out, IF they go by vehicle miles. However, that might not be the case with the OP's find, the risk is there.