[Ford-ferguson] 8N or 9N ? ?

[Primo Campos]

   Are the 8N and 9N blocks and trannys interchangeable  ?The reason I ask 
is that i have what should be an 8N by the stamping on the block. However 
looking at the differences @
Yesterdays Tractors it should be a 9N.  .Mine is  3 speed,has posts for foot 
rests,clutch and brake on both on left side,front mount 
distributor..8N-345044 is stamped at the left of block
casting#  on block is 8N B. So which is it?Thanks

Primo