this car has blue/grey smoke so far I have replaced rings, done valve job,had the fuel injectors rebuilt, changed the old fuel out changed fuel filters.and it still smokes bad! What should I try next all help is appreciated.

Most of the time, when you rebuild a non turbo 300d, you will find that the bores are out of round. The only way to make one stop smoking is to have the block sleeved and install new rings.

We order the sleeves and install them with our press and special installer and then have NAPA machine shop deck the top surface.

This has worked for us many times in the past.