<VV> bell housings

[Clark Hartzel]

The Chevrolet part numbers started out 625xxxx numbers and mysteriously
changed to 37 or 38xxxxx numbers later on.  If your bell housing has a 625
number it is definitely an early model.  All Corvair bell housings are the
same distance from the engine to the differential and have the same mounting
hole patterns.  The only difference (other than stick or Powerglide) is the
seal surface machining (same bore).  When they stroked the crank in 1964 the
seal and the flywheel face moved .070.  Put a seal in your bell housing and
mount it on the engine.  Look at the seal and the end of the crankshaft and
verify that the seal is on the O.D. and that the housing or seal surface is
not sticking out past the crankshaft where it will get rubbed by the
flywheel.  If everything clears, mount it and don't worry about it.  If the
seal or bell housing sticks out past the end of the crank you will have to
remove the seal, machine the face deeper and put a spacer under the seal
face to duplicate the later housing.  Or find the later housing.  Remember
whatever engine you are using to match the flywheel and clutch with the
engine not the car.  Late models use stepped flywheels and bent finger
clutches.  Early models use flat face flywheels and flat finger clutches.
That .070 difference I mentioned is what determines which clutch and
flywheel to use.  
Clark Hartzel, former CPF curator and keeper of the engineering drawings