Say there Chiphead, I recently rebuilt my 57' 6 cyl. with a fel pro gasket set and the plastic washer you are talking about I used for my oil pan plug.My engine runs good with no leaks so far.Check to see if that drill start in your oil pump for your lockdown bolt and nut is in the correct location from the top(BASE).Thats my only guess the rest of the bolters have really tried to
determine your probem GOOD LUCK. OL'55
