Rings are a possibility. The carburetion problem could have effected those cylinders ie: washing down the cylinders and wearing the rings. You could also have too much
oil going to the rockers, depending on the type of block you have and the mods that have been done. Heads may be flooded with
oil, and if you have a high lift cam, FE's are very prone to valve guide wear. The pcv shouldn't suck
oil even without the baffles unless you have too much oil up there. Just a few things to think about, there are lots more
Which cylinders are low on compression ???
Joe