My 84 El Camino is in the shop right now getting a rebuilt 200 4R trans installed. Now for a rear end upgrade. I'm pretty sure my current gear set up is 2.73 and with the new overdrive I think I can kick it up a notch. I'm thinking 3.23. Can I just buy the parts and have my mechanic install them? Or do I need a new rear assembly. I'm hoping I can just get the parts installed.