1988 case breather. Bottom end filtered to atmosphere. Good oil pressure, fresh oil. Oil tank (when open) and breather have smoke coming out. Took vent hose off and smoke from there and breather. Oil returning to tank OK. Bypass plunger on the oil pump working. Any suggestions on what to look for? Less than 1500 miles on a top end. Went on a short 400 mile trip. Oil lamp came on. and smoking problem started. Went through the S&S oil pump, (gaskets and new keyways) looked OK. Oil looked bad, black. While inside the cam cover changed cam. I sure that the timing marks and breather gear are right. I'm leaning towards pressure being built up somewhere but I'm confused as to how and where. Any help would be appreciated.