rear end question?

the only gear ratio close to my 3.55 was 3.23. it came out of a 68 fury. still a 721 case and thats what i had. for 84 bucks i think i did alright. how much will the 3.23 gears change my running from the 3.55. thanks again for all the help. still confused on the end play adj but will figure it out when i put it together.