How to Change Rear End Ratio

Im trying to gain some acceleration, so I am trying to go from a 3.08 to a 3.42. My question is how in the world do I change it, do I have to get a part or is it something I can just change on my current setup?

Ring and pinion in the diff. has to be replaced, this is not a dyer job, special tools and know how, unless you have had some experience in this job get a pro to do it.

you would be much better leaving it to a pro, you have to change the ring and pinion gears and getting it all set up properly is like artwork, i even rebuilt my own trans but i wont touch a rear end

you would be much better leaving it to a pro, you have to change the ring and pinion gears and getting it all set up properly is like artwork, i even rebuilt my own trans but i wont touch a rear end

How would you know who to trust with something like that? What should the shop specialize in?

How would you know who to trust with something like that? What should the shop specialize in?
when i had my car done, i left it to someone who has done lots before, he builds race rear ends and he does them right, for a shop, you just have to look around, some may have a guy that good at doing rearend others may not