Oil consumption 300d

We own two 300d's and love them especially here in California---no need for a smog test!! Our 84 300td's (201,000 miles) engine is strong and does not burn a drop of oil. Our 79 300d(190,000 miles) burns 3/4 of a qt. every 400 miles. It has been doing this since I bought it from the original owner almost 5 years ago. I've had a compression test done and the mec. said that each cylinder tested out around 360?? My current mec. said to continue to drive it and continue to put in oil when needed. At some point he says I'll need to overhall the engine (when it won't start). Should I continue to drive it as I have been. Even though I put REDLINE in at each fill-up, it smokes alot. One advantage, nobody tailgates me! Any help would be appreciated.