Changing camshaft questions
 

I wanted to ask if it is neccesary to have the metal pieces that the cam contacts resurfaced when installing a new cam.

that would be wise to do... you don't want your new cam to wear down fast,, please have a machineshop resurface the rocker arms :dancing:

yeah, it's a good idea, because the lifters are worn in a certain way, and if you put a new cam into it, the lifters will wear the cam in a negative way.

The tops should be milled also because you are correcting the flatness on both sides. You will then need to shim the towers according to how much was removed.
A friend of mine works in a speed shop and he told me you shouldn't hang the engine on an engine stand because the weight of the long L6 will actually bow the block while you are assembling it. It should be setting on the motor mount area and the rear of the block.