[olddog]

This is one of those questions that a person may give different answers on different days.

I have read so many stories of issues with SO blocks having sleeves and other repairs and problems, I think a would prefer purchasing a disassemble engine over a running engine. When you realize what a 427 SO is, it's easy to suspect that over the last 50 years it has been thrashed and crashed a great many times. On top of that, there we so few of them made. That said for me purchasing a running original 427 SO is scary, and at the same time the owner believes it should fetch the premium price.

I would be less scared of a 390 stroked. There were millions made and finding a good low mileage never abused block is easy compared to a 427 SO. This fact also makes them less costly. So I could pay less, and have a better chance of getting a good engine. I'm liking that feeling, more for less!

Now an aftermarket new aluminum block with a much better oiling system, in my mind delivers the most value, in terms of what it is and how it will perform. Of late there has been talk of quality issues with these blocks, so this is an engine I would feel more comfortable purchasing in running condition than disassembled. The owner also feels it should fetch a premium price. So you are going to pay more to get more.

But if the question is a person has an ERA and has each engine running in another car and he will install any of the three engines and sell it to you at the same price, regardless of which engine you choose, I choose the newer aftermarket aluminum FE.

PS
Now if the person was trustworthy and had a good story and papers to back it up, I might be swayed to go with any one of the other two engines depending on the story.