I've been running wvo in a 7.3 for about five years (60K miles) and on my 300d for about 6 months. I have DFA (now BFT) system on the stroker and love it. I have plant drive on the 300d and it is just as good, just requires a little brain power. i have a 4bt and now a 6bt. I am going to go with a plant drive system (or maybe my own-but customer support is great with them) and i am wondering if the FASS is necessary. i don't know if the components in the stock pump would tolerate the heated wvo? Anyone have experience there? I know i can hook up a FASS to run both and blank off the stock pump, but that costs about 5-600 bucks!