Didn't mean to turn you against wanting to do a rebuild yourself, Jim, doing one can be fun and a great learning experience. And, with today's internet you can find a ton of videos on what to do, especially on a small block Ford or Chevy.
But I will relay this story. My one son has a rpu with a 455 Olds bored out to 468 cubic inches. We had a local machine shop do all the machining, and we assembled it with the best parts we could buy. Right off the bat it was burning oil in a couple of cylinders. So, we tore it down to see what was up.
We found a couple of questionable piston rings, but nothing real obvious, so we rebuilt it a second time. This time it smoked out of several different cylinders. By this time my son was getting discouraged and we were tired of pulling and tearing down the engine so often, so we decided to use a local race engine builder, Mike Thompson Race Cars, to build the engine for him.
When it came back we installed it and it ran like a clock, no smoke and tons of HP. I asked him what he found wrong, and Mike, being kind of a quiet, gruff guy said " A lot of little things !"
Same with the 306 cubic inch small block Ford in my son Don's T bucket. After we built that motor a valve stem broke off and it swallowed a valve. We took it to Mike and he built that motor for us too, and it makes good HP and doesn't use a drop of oil.
So, it just shows that while we have built cars from the ground up, we are not engine builders. The 331 stroker in my 27 was one we built, and it has been good, but more and more we lean toward just letting someone who knows this stuff do it, or buying a crate motor.