I have some old AC110s that Ive dug up was wondering if it would be too much for a 10g tank. I will be modding them as well

modding them how? to reduce flow?

yes

I have the old version of the 110 the AC500 on my 16G bowfront and it makes a great refugium once its modified a little. Rather than shortening the length of the blades on the impeller I found sanding the tops off making it less tall overall worked better for keeping in in balance and quiet.

i was thinking about leaving the impeller as it is and turning the intake tube left.

That will not reduce the flow enough for a 10G. These things put out a lot of flow since they are designed for a tank 11x the size of a 10 gallon.

I ran a ac110 on a minibow 7g for 8 months before I upgraded. You can change out the impeller to a ac50 one or just cut the stock one. I also cut the tops shorter like AZDesertRat did. and he's right turning the intake to the left will not be enough.

Cut half the fins off. Worked as an awesome fuge for my 20 long for 6 months till i upgraded

As suggested above, I think your best bet would be swapping out the impeller for a smaller one. This way you get the lower flow but you know the impeller will be balanced and quite without any hassle.