I just bought a 91 2600i 5sp. Im losing oil at about a quart every 1000 miles. No dripping oil leaks and no blue smoke. I find this kinda wierd cause thats a lot of oil to be losing without seeing any heavy leaking or smoke. anyone else had this problem?

 

Worn rings could burn that much oil without noticeably excessive smoke. You don't say how much mileage is on the engine. An oil treatment like Seafoam or Marvel Mystery Oil could help if it's only stuck oil rings.

 

Its got 142000 on it. I put some marvel in the gas tank last time I filled up. I was a little weary to put it in the oil thinking maybe it would break some stuff free and cause more oil consumption.

 

Check your PCV valve (just pull it and shake to see if it rattles: if it doesn't, replace it).
Next, pull the plugs and see if they're dry and a healthy tan color. Have your compression checked, and do a cold engine static check too; a cylinder having a cylinder pressure HIGHER than its neighbors means oil is running down the valve guides into that cylinder overnight, giving it a better seal.
If you lose oil via the seals, especially around the area near exhaust system components, you can lose it onto the warm/hot parts, and the slipstream will distribute it all over the place with no apparent concentration anywhere. This means your venerable vehicle is rustproofing itself with that oil.
Another couple of simple checks are to remove the oil filler cap and check for pulsating pressure with the palm of your hand, then run your index finger around the end of the exhaust pipe to see if it is sooted.
The auto industry is squeezing everything it can to improve fuel consumption, and oil viscosity has been no exception. At your mileage you could go synthetic, or use a heavier summertime oil, say 10-40W and drop back to 5-30W in winter for example.