Owen_Dyneto wrote:
When removing guides with the cam and cam followers still in the engine, I've always simply driven them down about half way until they are just shy of contacting the lifter or tappet, and then snaping off the bottom with a chisel and light blow from a hammer, and then driven the remainder out similarly. Easy and straight-forward, no complications, done dozens and dozens of them this way.

Just exercise care as they are driven downwards that you snap them off before they contact any part of the lifter assembly!