Increasing size of perimeter foundation

[Patrick Sears]

Hello, I am looking at a 1985 single-wide MH 14'x72' on a perimeter brick wall foundation in a deeded lot MH subdivision (real property). Needs a lot of work and might make more sense just to get a late-model repo towed in. I was wondering what it might cost to have the foundation increased to accept a 16' wide x 72' instead, since there are so many of those out there now. Also, what land mines should I look out for when setting a new home on an existing foundation? I know there is the possibility of size variations between manufacturers; are there ways to adjust for minor size differences when setting on a perimeter foundation? Thanks!