72 340 4 spd question

What I see there is a OD unit out of a truck, (called a Miser), but he's got the one piece of linkage on upside down. I could be wrong, but ask for the diameter of the front bearing housing. Top is "A" body OD unit, bottom is "B, E" unit , note the iron case.100_1324.JPG 100_1324.JPG