You are going to have bigger issues if they haven't been addressed yet, brakes and steering. 5.38s are stock for the 2As but some switch over to D44s from a 3B or early CJ5. Most recommend buying the Warn Overdrive for your current set up and keeping the stock axles. I'm assuming you are using the Spicer 18 t-case.

This is a site were guys have made these type changes http://www.earlycj5.com/forums/index.php? and this site is for 2A people but more resto http://66.70.101.194/forums/default.asp

There is somebody on The CJ2A Page with a Chevy 327 (piginajeep) but not sure what he has for axles. <img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />