I finally wathed the video GMC, cool stuff for those interested in doing such a thing. I have repaired a few of the older style, that were non internal voltage regular, and some that were internal, but they were older also, like late 70's mid 80's. Not hard at all. Also put brushes in starters too. I like to hold on to OEM stuff as long as I can not to mention saving a few bucks, even though sometimes, its reall not worth the headache. Just buy new and be threw. (through).
Going from a 145 to a 250 you wouldn't need to, because they use the same case. But the 105 uses the smaller style case, so the diameter of the case puts the pulley about a half inch further away from the centerline of the engine. Just going to the next bigger size belt will work fine. Even using to old belt will work, if you have enough arc in your self-adjuster. I didn't need to swap belts going from a 100 to a 140 because there was enough swing in the adjuster to allow it, but it was a bit of a job getting the belt on.
