wow I am redoing the rollers on my 86 as we speak.....I just placed my order for replacement rollers from
http://trailerpartsdepot.com/items.asp?Cc=A%2DROLLB&iTpStatus=0&Tp=&Bc== I'm going super cheap and getting the factory blemished ones.....
I cant see a reason why the 3" would be a problem, the bearing surface on the black rubber rollers on the spindle itself is only 1 1/2" and the rest overhangs so the only difference is that the boat now sits on 3" wide rollers instead of 3 1/2" which I cant seem to reason why it would matter.
At least thats what I hope because I have 24 coming shortly.!!