Kicker Idler Shaft Removal.

83 500 wanting to change kicker idler shaft out to later "eared" style. Someone replaced LH case half with earlier one at one time. Last one I removed from a case I tapped it to 7/16 fine thread and used a slide hammer. The replacement, later style, was easy to remove because case was cracked thru it! Installed it with a valve guide installer. Tried blind hole bushing puller and a little heat to no avail...Tap it and install grease zerk? Any ideas??? Thanks in advance.