'85 Chevy carb problems

[westcasey]

I've got an '85 Chevy 3/4 ton 4x4. It has the same engine in it as the Corvettes had that year. I've had the dang thing in the shop several times because I don't know anything about carbs. It soots up the spark plugs really bad about a week after replacing them. I've had the carb rebuilt and adjusted 3 times by two completely differnt shops. It still does the same thing..... soots the plugs up and misses really bad. Can anyone help me out? NO BODY can seem to get this dang thing to run right. It ran perfect until one of my employees ran the thing out of oil and I had to replace the engine!!!