dist. doesn't fit

the old points distributor from my 273 fits in the new 318, i have one new dist. from an old military 880 that requires an o- ring and another new dist. from jegs that also requires an o-ring. neither of the new dist. fit on the block, or the interfence is just tighter than i am comfortable with. it seems that the general concesus is that these are a static fit anyways. is this a correct presumption?