I just changed my oil today and read aprx 30 pages by the good Dr. on the topic to be sure I picked up the correct oil. It seems to me there are some issues with flat tappets, my question is would it be worth swapping in roller tappets? Is this possible? I try to stay out of the motor and tranny as much as possible, but I am kicking around the idea of picking up a 4.0 block and building up a stroker in the garage over the winter. I dont know if tappets can be swaped. Also is the 4.0 solid flat tappets or hyd flat tappets?