There's a lot of ways to do this.
Autozone, Advance, etc, all sell reman engines, mostly longblocks these days.
Most of the Ford magazine and online shops sell a wide variety of short and long blocks, from mild to full on race.
Ford sells them via both plain old Ford reman and via SVO, etc.
Try DSS, they seem to have a good reputation.
All that said, unless I was in a big hurry, or had a totalled block, I would either redo what I had, or get another to rebuild locally. My local machine shop is still less expensive than the other alternatives, and stands behind their stuff. B and T Auto Machine in Beaufort SC.