Ok me and my friend just removed the rods and pistons from his block. he plans on getting it bored at a local machine shop. Now we would like to know if it necessay to remove the crank from the block or can we just leave it there?

 

Yes it is a must. take your time when removing the crank from the block not to damage the journals.

With all bores and hones you will have the need to completely wash out particles to protect your bearings, also if you plan on reusing your bearings remember to mark them with a magic marker or something.

Another thing to do is take one piston with you to the machine shop so they can properly bore your block. if the machine shop doesn't ask or doesn't measure your piston prior to boring take your block somewhere else.