i have a vette that sat around for awhile. well when i bought it i fixed a few things but noticed it was using oil. about a quart every 250 miles. well i have put about 6000 miles on it and i have been checking to add oil and is using less and less. i say about a half quart in about 400 miles. so i assume either valve seals have sealed up or rings have. does this sound right or possible ?