Yeah I screwed up the title with the dollar sign and couldn't figure out how to edit. To clarify, the guy is asking $400 for a complet 1975 400 with all pulleys brackets ect, supposedly a virgin engine that has never been apart. So we thinking this is a decent deal then?
It's high considering most of it is not useful if you're building a stroker. You can't get much over scrap for low-po mid 70s stuff anymore either so selling parts you don't need to recoup may not happen. I paid $200 for a '71 400 block a while back when low deck strokers gained popularity. I couldn't give away a complete steel crank 440 a few years ago.
It is a fair price if it is in good shape. Unfortunately you won't know that until much later in the process. It is a good price if you need all of the external parts. If all you need is the bare block then you might be able to find something cheaper.