[ERASER5]

Here are my numbers. I measured from wheel mount surface to wheel mount surface.

1970 GMC 1/2 ton truck long fleet with leaf springs

64-1/4" Front with 73-87 disc conversion

63-3/4" GM 12 Bolt 1970

62-3/8" Dana 60 1969

I have a 72 also, but the width will not be any narrower than the 70.

You can see that the new disc conversion is only 1/2" wider than the original rear, or 1/4" each side.

The D-60 is almost 2" narrower or 1" each side.

Does this answer you question?