Interesting, and I think some information is wrong ad crossovered.Anyway,the 233 is probably the best.My really old conversion is with a 231? case(91 S10), and I had to cut out the top of the beam above the /case, run vac hoses to the chamber to switch the front axle(mounted the vac chamber behind the rf front wheel housing, and had to add an on/off switch, to tell the computer it was in low range,so transmission would shift properly.Many years ago.