03 6.0 HPOP to a 05 HPOP
 

Can a guy change the HPOP in an 03 and install the 05 style HPOP? Of course I would have to change the cover but the rest of it looks like it would be compatible. I was wanting to update to the 05 style because I belive it's a better pump (not aluminum). What are your thoughts?

You would have to change the branch tubes and the oil rails also. The heads would have to be removed and the rear cover would need to be removed also (which would require the engine to be moved a little by loosening the motor mounts). Easiest to do w/ the engine out. You would also need to a harness change for the new ICP sensor location. Obviously you would need new standpipes and new HPOP cover as well.

Not worth it. You would be better off with an upgraded pump.

I agree with bismic, go to a good rebuild or upgraded HPOP. It is not worth the hassle or parts cost to swap.