oil consumption
 

My 90GT usually needs a quart of oil at about 2500 miles after an oil change, more now since the rear main is drooling. Just curious, on average, how much oil, if any, do you have to add in between 3000 mile oil changes?

Never have to add any on my '89 5.0 with 72,000 miles.
Never have to add any on my '94 4.9 van with 79,000 miles.

My GT takes about a quart every 1500-2000 depending on the oil. My Fairmont uses oil as an undercoating so 1 quart every 1000 miles. The Jeep (which has no revelance on a ford site :D) uses 1/2 quart every 3000 with 235,000 miles.

back up to the top for more opinions, thanks everyone

It's not uncommon for a stock 5.0L engine to use 1/2 to 1 quart of oil between 3000 mile changes. Some use nearly no oil. I wouldn't lose sleep over it. The engine can still run fine for 200,000 miles. I think there are probably two reasons why some use a quart and some use none:

1) luck of the draw - a side effect of high volume production
2) how the engine was broken in - how well the rings seated

This is just an observation, I have no imperical data to back it up, but I have noticed that the factory 5.0L engines with forged pistons and low tension oil ring packages tend to use more oil than the hypereutectic piston engines of 1992 - 1995. Anyone else notice this?

Quart every two weeks
 

Yep,
One quart every 2 weeks. Number 5 has a bad valve seal (I hope) or a bad valve guide (I pray not). Unfortunately, I have been driving it like this for almost a year and almost certainly am jacking things up.
Oh yeah, I have to change number 5 plug every month 'cause it's covered in oil and fouls.
I hate to admit it, but I really haven't had the time to pull the head to have a look-see. Can't afford to have the car down for that long, plus you pull one, you have to pull the other.
Sorry this is so long.

Mine took a qt. every 3,000 miles. (when stock)