I have the 312 on an engine stand. The cylinders, mains and rod bearings/journals all check out; cylinders are standard bore with newer pistons, rings, etc. The engine has less than 20k on the previous owners rebuild. What doesn't look good are the cam bearings. A new Mummert 270 is ready to go in and I want to replace the cam bearings using a Proform cam bearing remover/installer. I really don't want to remove all the pistons/rods and reinstall them if possible. The old cam lobes look good but the journals are scuffed and the lifters cam out easily using a magnet. I can't see a good way to get this done with the rotating assembly in place. Do I bite the bullet and take the internals out? Thanks.

57 Black Tbird 312/auto