My oil burning pig. Pics too!

What do you mean the seals are .313"? Is this the spec, or some kind of measurement? They should be a bit smaller than the stem without a valve in them. .3125" is the nominal valve stem size. A .313" spec seal might be for an oversized valve stem.

With the issues you have, I would mic the valve stems top, middle and bottom to see if they are all close to .3125". Then flip the valve and try the feeler gauge in the bottom of the guide, in the port, to see if the guide is tapered. Regardless, a good seal can take care of oil with some guide/stem wobble..... but only so much.

This article has some info on the seals:
http://www.enginebuildermag.com/1998/07/valve-stem-seals-materials-and-designs/

One thing it notes is seal concentricity on the valve and guide.