locating large round parts on CMM and clocking them

If they are straight cylinders, and there is not even a single feature except for the straight walls and the faces, you will just have to use machine axis for rotation. If it were me I'd probably try to find some sort of score mark on the face that stands out

it has very many features to measure at all different angles

Oh, then you can pick any feature that is easiest for you to measure on the side for the rotation, whether it be a slot, or a circle

that's not what I am talking about, how can I locate this heavy part on the table and be able to move it and turn it to the proper clocking with it being so heavy?

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Sorry about that. I overlooked the "put on machine" part when reading your statement. Others here who measure these large parts have had them dropped off with a forklift on a pallet. Or some have access to cranes for lifting them onto the CMM. Adjust clocking while part is lifted by the crane. I can't say I'd be able to safely do it myself without a crane.

I have a 10-ton gantry crane that goes over both my machines.  If you are looking for 'a lift', well, not much we can do about it.  as for proper clocking, that's what the alignment is for.

I have a crane, setting the part down is not the issue, what I do now with the not so heavy parts is set the part on the table and then push it against two standoffs to locate the part and my program will move the probe over a hole and then the operator will rotate the part keeping it up against the standoffs so the probe is centered over the hole, this is how I get the proper clocking of the part so my probe angles work good.

but with this heavy part I will not be able to move it by hand or rotate it.

You will have to get it as low to the table as possible, and rotate it while still suspended by the crane. That is how they set up molds on our Injection Molding machines. But they also have guide bars to help.

with GOOD ground blocks for it to sit on, you should be able to rotate it as much as you want to, just don't put 'part' on 'table', put it on precision ground parallels.  I can slide 3-4 ton items on the table when on good parallels.

Well I guess first silly question would be what machine do you have? 
I have a DEA you can park multiple cars inside, with an overhead crane, and parts larger than the average car. We have a steel large steel fab table with a bunch of modular tooling blocks. We just set up our table and then gently move the part into position against the stop blocks. 

In your case it sounds like you don't have that option. Run a 4x4 across your machine against the columns and butt the part up to that? Better yet a 4x4 with some blocks sticking out of it to catch the part in a V-shape to center it and give your something to rotate against, spin her into place and set it down. If tis too heavy to rotate, then get a ratchet strap and a piece of pipe and make a strap wrench. Mark on your table with a sharpie some reference marks you can use to clock the part. 

There are ways.