Blue is definitely oil. Do a compression test see if its the bottom end. Check the oil make sure the head gaskets arent still leaking.engine ran hot and blew head gaskets. Replaced heads gaskets and had E7 heads rebuilt at same time. New valve stems seals and guides. Now engine has blue smoke. Short block only has around 1000 miles. Do you think broken oil ring???. has great oil pressure 60psi stock engine with a B cam and BBK headers with Parker funnel web and 650 Quickfuel carb. ANY IDEAS ????