how to install a camshaft

I have 1991 jeep Cherokee 4.0
Do I need to remove the head to install a cam shaft...:gee:

Yes.

Yes, the head needs to come off. Get an engine hoist and remove the head with the intake and exhaust manifolds attached. Your back will thank you. Besides the cam you will need new lifters and do a proper break in.

And the radiator with everything else in front of the engine. Take a tape meaures and check just how much clearance you will need to slide it out.

Be sure to pre-lube the new cam prior to installation. If the cam supplier does not provide it with the cam, get some. And I agree with Talyn, new lifters must be installed with a new cam as the lifters wear uniquely not only to a particular cam but the lobe it rides on. When doing valve trains, it is important to keep each valve's components together. With a complete new setup, you can just keep the pushrods and rockers paired together

Some folk say to give the pushrods a very thorough solvent cleaning prior to re-installation to make sure the oiling passage is clear. I agree with this as it is cheap insurance for getting oil to the rockers.

On my 2000 I only need to pull the radiator and the grille trim (at least on a 97+). The condenser can be propped out of the way enough w/o disconnecting the AC lines. I would think it similar on your 91.

I ws not suggesting the AC be drained as you are correcr Sir, the condenser moves. But yes, grill and radiator to be sure. Better than having to pull the engine as you do on some vehicles...