Hope this is not too far off topic, i am looking at a Navion to purchase that has been modified with an IO-520A engine. It is a run-out so I'm assuming we'll be changing out for a rebuilt in the near future. My question is, is there anything I need to be especially aware of in regards to this particular model engine? I am looking at couple different planes with different engines,(io-520BA, io-470H) but his one has most of the options etc I want. Just want to know what the reputation of this model engine is.