I installed the stock distributor with number 1 piston on TDC and the distributor won't sit flush. There is a small gap, I can fit a flat head screw driver in there. I'm turning the distributor back and forth and at the same time putting a little pressure on the distributor and it won't go in any further. I took out the distributor and there is no crap inside the hole where the shaft goes into. I remove the slight rust around the base and lubed it up with oil and still won't go in all the way to sit flush..Any ideas?