What brand oil pumps are you buying ? I have a melling high volume pump in my stroker and having the same issue . It has less than 2k on it . I still have my old one that I took out before I built the stroker that you can have for shipping costs ,It had good pressure . But when I tackle mine and go through all that work I wouldn't
want to put a used oil pump in . It's a 4.0 right ?