What effect 1/4 inch longer irons?

Thanks for the replies

Another question that came to mind on this,

As mentioned at the start I was fit for Titleist AP2 so the specs on a 6 iron would be: Length 37.5 (standard) Lie angle 60.5 (2 deg flat)

So would that mean if I was using a 6 iron from another manufacturer which was 37.5 long should the lie angle also be 60.5

Does the lie angle remain constant once the length is the same? or can a different clubhead alter what the lie should be?