I have been using Mobil 1 full synthetic for about 9 years now, the last 7 with ZDDP Plus. Been thinking about changing back to regular oil after reading some past threads stating that using synthetic oil with a flat tappet cam will result in cam lobe failure. It has to do with the lifters not being able to rotate in its own bore properly because the oil is to slippery. It was also stated that synthetic oil would run off the cylinder walls and bearings with in a couple of days resulting in a dry start, were as regular oil would cling onto the surfaces. I started using synthetic oil because I wanted to protect my investment, I am not sure if I made the right desision. What do you experts think.