lower control arm shims

I'm going to be installing a 4.5 lift but I'm piecing it together. My question is about shimming the lower control arms out to get the correct length. I have a set of Pro Comp lowers but they are only 16'' center to center and I'm being told they must be 16.5 long. I see that in my Cherokee now there are a few shims but there is not a lot of room in the stock hole now and I'm wondering if they came with shims in the stock suspension. Hopefully someone can give me the info I'm looking for. Thank you for your time.

Yes, they came with shims to correct for sloppy work on the subframe. But I understand what you want to do. My opinion is that this is not a good way to add a half inch. The reason you need that length is so your castor angle will be correct, or nearly correct which will go a long ways to avoiding or curing any bump steer. If you have any and you have exhausted the usual suspects like track bar bushings and alignment issues, then I would suggest an adjustable top link to pull the top of the axle back to correct it.

The best cure at that height is a longarm set up but adjustable control arms will help to correct your caster as stated. You may end up with some bumpsteer and a harsh ride as well. but these are to be expected with over 4" and short arms.

I guess another question I have is , can I take the set I have and cut them and make them longer bye chance? The pro comp set I have has a slight bend in it but I'm wondering if I cut the ends off and buy some tube and reweld them back on.

Of course. You can make your arms any length you want that way. Weld up some brackets while you are at it and have some long arms.