There will be significant differences between the two setups that you'll have to get used to, as trajectories, etc., will be different. I think any difference due to the arrow length will be lost in these other differences.
There will be a difference in sight picture, whether you pay conscious attention to it or not. This probably would not affect your shooting until the arrow point comes up close to your point of impact. At normal instinctive distances of less than 30 yards, the arrow point is enough below the target that a half inch more or less of arrow length will probably not be noticed.