Which bellhousing?

Can anyone help me out IDing which bellhousing I need to complete my 4 speed swap? It's the last piece I need to complete my engine. I have a B 383 and I need to know what bellhousing casting I need to fit up my 833 to it. The 833 is an overdrive unit with the 5.125" input bearing retainer, having a hard time deciphering which casting number would fit this application in an A body, if any. Am I going to need a truck bellhousing? :banghead: