I went from a 144 to a 151 on my 06 switchback. Wasn't that bad. Hardest part was getting some of the tunnel and rail bolts out. I ended up takeing one bolt out at a time cleaning off the tread lock and greseing it. Then put it back in, then taking the other side bolt off. One bolt will always stay in and spin. Hold the rear up, take the exhaust off, drain chain oil, take chain cover off, Chain off, bottom gear off, unbolt the whole rear sys and take it out, lossen the bolts on the left side off the drive axle, slide the whole axle over to the left so the gear side (right side) comes out. It took me one night after work. (Never did it before) Make sure you have the rear cross tube of the 151 rails, 144's don't have it. Remember where all the washers go.
