i've heard once before that if u use a certain type of oil for a long period of time, it is bad to dump sumthing in different at once. say, if u use regular and then switch to synthetic at once? i was told i can use synthetic in my 86 5.0, and i wouldnt need a time to adjust or w/e u call it. anyways just curious.
:banana: i love that guy!
Go ahead and dump in some synthetic if you want. You're not going to hurt anything (except maybe your wallet). That scare "may" apply to amsoil, at least back in the day, but with the refined conventional oils available today along with higher engine operating temperatures, there's not going to be near the sludge in the engine as in the olden days when the warning was probably true.