I used the sierra alternator, but the pulley will fit the std one. You need the alternator bracket. You will need to machine the alternator bracket, to move the alternator over. There is a like a notch where the alternator mounts - it just needs grinding flush.

You will need to take the engine mount out completely to allow clearance, and slacken the cradle mounts a little. THe engine drops down and then u an get the pulley on. It's very tight. When u are jacking it back up, if it hits the chassis when u are jacking it up, then u really need someone to lever the engine to one side - this is why the box mounts are slackened.

Once the engine is level, there i about 5 mil clearance - with the pulley machined down!

I got my pulley balanced - it's very heavy.