Make sure you are careful getting the nuts off in the engine compartment. You can bust them out of the fiberglass housing if they are seized. I have cut the nuts off with a cut off tool just to insure not breaking them off and then bought new nuts..
Looking for a picture of a 1972 B-body Radiator cap with the Max Cooling. It is Part # 3574154 and used with the Large overflow bottle. It is used with this recovery system bottle I sold awhile ago..