The 6V blower has two sets of ribs on the case where the long bolts attach the blower to the block.
The 8V has three sets of ribs.
The inline 6 has three ribs and attaches with bolts thru the flange at the base of the sides. And one side has a lip on it where it kind of hangs on the block.
Don't forget that the bearings on the end plates need an oil supply and a drain, too.
Hope this helps.
Frank