I noticed today that my oil was about a quart low in my cough cough truckmaro, 355. I'm about 1k shy of my oil change and usually am down a tad less then a pint at oil change time usually all city some 55mph highway. Last week I added a bit of oil for a short trip up I25 about 120 miles. With gearing and tires 75mph is 3k RPM usually I float around 80-85mph 3100-3200. When I checked the oil today it was a full quart low. As far as I know the engine is in good condition, 20,000 miles since it was fully rebuilt, no smoke on start up and as far as I know none going down the road very small oil leak is all I know of. Fuel milage on the highway was great even pulling 12in of vac, 21MPG, 13 city. I know that at high RPM a small amount of oil will blow past the rings but a quart worth? SO my question is how much is normal? I'm going to run a leak down and compression test this weekend but I could use some opinions first.

 

use to be a quart every 1000 miles was acceptable, any more if you need a quart between oil changes people think they have a problem. considering your engine speed it doesn't sound bad. if you really want to check things out you can leak it down and then you'd have a hard number to go by.