I have a 1983 Chevrolet El Camino with 357,000 miles that I recently did the Auto-Rx thing and now I am on the Maintenance Dose, car runs great but at startup there is a puff of grey smoke, probably bad valve seals or bad valve guides, it has been doing this for about 18 years, do I fix it or live with it and if I do fix it will the car run better and have more power, the car does not use any oil, meaning I only have to add a little bit between oil changes, I am currently running Amsoil 10w30 100% Synthetic as I had about a case of this before I started Auto-Rx, it seems to blow a little bit more on startup than when I ran Pennzoil Platinum when I started the Maintenance Dose, do I go back to a Group III Synthetic or maybe even back to conventional oil with the Maintenance Dose, the car does not smoke at all while I am driving, yes I did use conventional oil during the Clean and Rinse Phases, anyone with any experience with Small Block Chevy's please give me your opinions.