"On air conditioned cars, rotate the crankshaft until the number eight cylinder exhaust valve is open, to allow clearance to remove the right bank cylinder head cover and the heater housing." This really works, you get the cover loose, move it up and twist and pull sideways and it comes off. Or, you can lower the back of the engine an inch with a jack under the rear mount and remove the six bolts holding on the frame cross member. Or, you can remove the heater core, careful not to crack the housing at the bolt holes, run a dull knife around the butyl seal and off it comes.