ok fellers i recently put a 4bbl on my 351m. the only thing i did different when installing was i used felpro cork rubber gaskets instead of a valley pan. now it knocks terribly when it gets warm. and in gear its sounding like its getting no oil at all. if you throttle it to about 1-1200 the knock goes away but then the lifters are tapping constantly. the only thing i can think of is it just so happened the oil pump is starting to go bad. i know it needs new rings because it smokes on start up ever since i have owned it. being about 6 monthes. if the oil pump is out then i will just park it and begin forkin out money for the 400 sitting on the stand