You can use sticks with magnets on the tips to hold up the lifters while removing and installing the camshaft. There is also a cam shoe tool that you put on the back of the cam to slide it out and in alot easier with out damaging the cam bearings. If ts an Etech engine turn the cam gear timing mark to about the 2 o'clock position to have the lobes in position for removal and installation.

Good morning and thank you thats exactly what i did ,but #6 intake lifter was stuck had to bang out to get cam out,checked height on all H rings and they were fine,

I know you already checked the H ring but triple check that H ring, make sure it didn't move at all. Also make sure you don't have any boogers/burrs in the lifter bore. Make sure the new lifter slides in and out just like all the other lifters.

Good luck

When i checked the H ring i noticed it turned a little bit ,i turned it back straight and set all of them with a height gauge ,and had to sand out a little to slide easier, I personally think that Mack H ring is a bad design