Letter on position 1 (f) changed: 10 words buns duns guns huns muns nuns puns runs suns tuns Letter on position 2 (u) changed: 4 words fans fens fins fons Letter on position 3 (n) changed: 6 words fubs fuds fugs fums furs fuss Letter on position 4 (s) changed: 3 words fund fung funk