Will I reget using a 3.23:1 posi rear end instead of a 3.55:1 in my Blown 440 mopar?

yes you will see a difference with the 3.55 gear, the 3.23 is a great cruising gear but if you want a little better take off I would go with the 3.55, it's still not so low a gear that it's not freeway friendly, the 3.55 is a good in between gear.