rear end

Well I have a 742 chunk with 323 opens in it in the garage, so I was going to get new ring and pinion gears with a spool anyway. I have been told that I need at least 430 or 456 gears for a mild 318 build that we are doing. So I was just thinking that if the one in the truck would work with out too much modification that would be the way to go. I have seen people on here talking and on E-Bay about shortened housings only going for 200.00. I am new to this portion of the MOPAR game so I am still learning.