my '70 T'all always blows out a plume of smoke upon starts. The first thing I tried was replacing the valve seals and valve cover gaskets. Then tried a different oil for high-mileage engines (altho it has around 35k). I can't remember the brand (penzoil, perhaps?), but it has a higher viscosity and some amount of teflon in it. It's also supposed to fill in some of the small gaps in the cylinder walls or some such. Nothing seems to help. HALP!