Installed new valve stem seals

I can't do much to mine because of a workmens comp injury 2 years ago. Its not on the road just sitting waiting on me to come out and play with her. When I do start it after sitting awhite she runs really smooth for about 30 minutes or so. Then she starts missing and if I pull the plugs the ones toward the center of the engine have oil on them. The others have no oil so I think thats my problem. Its a /6 showing 57000 miles but sit for a long time.
Any ideas if I'm barking up the right tree?
I may just have her pulled to a garage so I can get something started as far as completion. If workmens comp ever settles with me I can do a lot on my own, but can't take any chances geting caught till then. They pay me to well to mess up.
thanks for any advice