Part # 7224453
Valve Guide Driver

Even with heads brought to 275F (oven) and the old guides machined down to the c-clip, pushing the old valve guides out can requiers some pretty good smacks. The tool has a thru-hole in it, right below where you will hit it with your hammer. In my case the hole collapsed, resulting in a crooked top surface where you hit it. You will get the old guides no problem but I would recommend blocking that hole with a pin or machine the head off pass that hole on a lathe.