Will a 1998 3.3flex fuel engine interchange with a 1998 3.8 engine ? I have a 98 grand with a 3.3 and a bad transmission and I can buy a 98 with a 3.8 and a rod knocking . I will have all the parts to change it over but is it worth it (both vans are complete). What will I have to change over is the question I guess , anyone out there done this??????