For a idea of what it would cost to build a 348 / 409 try www.dr409.com They list any part you would ever need, and they also provide full machine shop services. Definitely more expensive to rebuild than a small block, not much more than a big block though. And like you they are in Minnesota, New Ulm. I've been sitting on a 348 and a 2-4 barrel 425 horse 409 for 25 years. I've been contemplating the 409 for my 50 pickup. It would be different and fun.

John