A*A*A With 4 A Levels

If I am doing 4 A Levels and my predicted grades were to be A*A*AC despite needing a A*A*A would I still be able to apply for thy university or would they require a minimum grade?

You can definitely apply, since many will only give you an offer based on 3 A levels anyway - just make sure you meet the requirements in any compulsory subjects (e.g. if they needed A*A* in maths and further maths but you had A*A* in maths and physics and a C in further maths you'd have a problem).

Universities only look at your top 3 A levels.

This is one of the reason why its pointless taking 4, and given you are not going to get a spectacular grade in the other subject, the best idea would be to drop it and concentrate on the other 3.

As already said nearly all universities for all courses only require 3 A levels. There are a couple of course I have come across in Imperial and I think Cambridge where if you take 4 subjects they require grade A. You would be best advised to not take unless your 4th is Further Maths.