I have a FE 390 with stock heads and Edelbrock Performer RPM intake. 590 miles on engine since rebuild. I recently replaced my intake gasket because of a leak in the rear. The first 150 miles everything went fine, didn't use a drop of
oil. (No signs of a leak!) Second 150 miles involved some highway and a lot of idling around the city. I started noticing some blue smoke from the left bank at idle. This time I used a quart of
oil. Third 150 miles was mostly highway driving and only used about a cup of
oil.
There is no smoke when the engine first starts. The smoking seems to start when the engine gets hot and is idling. I started unplugging spark plug wires and the smoking is coming from #7 cylinder. Against the advice of most of the FE posts on the forum concerning intake gaskets, I still used the FelPro 1247 Print-O-Seal intake gasket. Maybe I am paying for it now! I do have a PCV system and it appears to be working. The other valve cover is vented into the breather and both valve covers have the oil baffles installed.
Is there any way I can tell if the leak is intake gasket versus valve stem seal? Or, should I just bite the bullet and yank the intake? If I don't see any signs of gasket failure, then I can pursue the valve stem seal theory. I also re-torqued the intake hoping it was that simple, but to no avail.
Thanks for any advice. It is always appreciated.