Something of mystery here has cropped up with my 401 and may need some vertication of what I think is wrong here. I overhauled (with some help) an 401 and the engine is currently running good except for the fact that at highway speeds it uses oil like there is no tomorrow. Here is what I have done to try and locate where all the oil is going: Removed the spark plugs and took a close look at them. I am using just over a quart per 100 miles. There is no deposits on the plugs. They are normal with no unusual wear. I did a compression test and all cylinders are normal (160 PSI) and there is no variation between the cylinders. I check and replaced the PCV valve and hose going to the carb, although I did not see any problems with old PCV or the hose. After doing the above checks, it still is using oil at highway speeds and not using any oil at city driving speeds (under 45 MPH). I suffer no leaks at he head gaskets, valve covers, or the intake, and there is no oil mixed in with the antifreeze. I am using an Edlebrock performer intake with the Edlebrock performer carb. Here is what I came with: The heat sheild under the intake is allowing oil burnoff to occur due either being loose or has fallen off somehow. This would account for the non usage of oil at city drives considering that the RPM would be low and the oil pressure being somwhat lower (at about 45 PSI) verus that of highway speeds where my oil pressure is just above 60 PSI and the RPM nearing or topping 3,000. It is my feeling that with the above description as stated above that this would be the more likely reason for the oil burnoff. Note: there is no smoke from the tailpipes at any speed. I sure would welcome any comments from the experts in this field of mechanical experts.