I just swapped out a neck on a p-bass. The new neck fit, but was way tighter than any I've done before. All Fender parts too. I lubed it up with a little soap shoved it in and tightened up the neck bolts. After all that, I had to raise the bridge saddles up a bit to set it up. My question is... could the neck not be fully contacting the body at the heel? Bass plays and sounds good. Thanks in advance.