<VV> Bellhousings

[Clark Hartzel]

I don't understand why GM part numbers changed from 6 to 3 but I can tell
you the numbers starting with a 6 are EARLY numbers and the LATES start with
a 3.
A bell housing casting with a silver dollar size "dimple" near the end of
the camshaft is early and without is a late casting.  The casting ending in
176 is a late but was also machined as an early with a splotch of blue paint
applied.  The only difference is a .07 depth of the oil seal area.  You can
use an early housing on a late or vice versa as long as you check to see
that your oil seal lip is on the crank O.D.  If it isn't, put a spacer under
the seal flange so it doesn't go so deep into the bore.  
If you have an early and a late housing to look at, you will notice that the
tapered projection of metal around the seal area is skinny on an early and
machined deeper on a late.  Make sure the flywheel or flex plate is not
rubbing on the seal support area.
Clark Hartzel