Burning oil, LOTS of oil!

Do a compression check. That will give you all of your answers. Don't put those additives in your engine.

IMO, the SOHC engine is bad about accumlating grit in the spark plug wells. If not cleaned out, it goes straight into the combustion chamber when the spark plugs are removed. The results is a smoker.

If the replacement motor was a salvage motor, it could have happened before you got it. Not that it matters now.

Get an oil filter cutter. Inspect the filter element for bits of metal or plastic.

Check the PCV system. If not working correctly, this can increase oil use (not likely the amount mentioned). Also, if the valve cover baffles have been removed, this can cause oil to be sucked up into the intake.

Long shot, if a high volume oil pump has been used, I have heard of cases where the oil is pumped into the top end faster than it can drain back.

+1 on the compression check. A leak down test will let you know how it is leaking (exhaust, intake, piston/rings).

Has the motor always used oil?

Hate to hear things like that.

WOW!

5qts in 1k miles? That thing must be a smokescreen!

My 96 burns approximately 1.5 qts every 1k or so, due to poor valve guides/stem seals.
Early modulars are known to have this problem... I haven't heard of it in the PI cars as much due to improved valve guide design.

My car doesn't smoke at WOT or under heavy load(or maybe I cant see it.) The only time it smokes like a chimney is when it idles for a while or when pulling away from a stop light.

If you're burning that much the motor must be pretty much done.
I don't mean to rub it in or anything, but can you take a vid or something?

my motor has 3400 miles on it, it doesnt leak, or smoke, but i dont have a pcv system, i just have 2 breatheres, one on each valve cover, and it looses oil through them...

it sucks, i have a new motor, and it looses oil like an old POS.....

That's totally not normal and sounds like your engine has problems internally. Probably best to pull the motor and rebuild it.

In my experience, cars typically burn between 1 and 3 quarts of oil every 3K miles. If I am constantly beating on a car, the rate of consumption seems to obviously increase. My Mustang with 135K miles runs like a champ and doesn't smoke but still burns about 1 quart every 1500 - 2000 miles. My Grand Prix w/ about 165K miles burns about 1 quart every 1000 miles. When I had a Dodge Intrepid (drove from 135K miles to 200K milesit burned about 1 quart every 1500 miles the entire time I owned it.

Oil consumption in my Mustang has decreased by over 1 quart every 3K miles since I switched from Mobil 1 synthetic 5W-30 to Valvoline conventional 10W-30.

Yes, 5 quarts in 1000 miles is well over the service limit. I think the service limit is something like 1 qt evert 800 miles. Any less consumption than that and ford considers it "normal".
My 97 GT seems to use a quart every 2000 miles or so, and it has 167k miles. The mileage seems to be irrelavent, because it has done that since we got the car with 48k miles.
You definately have an issue. Do a compression check and a leak down test. These can tell you where the issue is. I seriously doubt it is the top end though. Most likely, it is the rings.
So may I ask what you are doing to destroy engines so effectively? Boosted? Uncontrolled detonation?

im going to have to say compression test will lead you to your source. you should have high pressure and constant, if you dont or it jumps up and down, youll know which cylinder(s) you are having issues with. im willing to say you have burnt rings

Yesterday I was searching info on engine internals and durability etc , and came across the postings in the provided link. I have no experience whatsoever with the product, nor do I know much about it, but it was a very interesting topic to read about:

Engine restore Does it work?