There is no aftermarket HC head offered for the Model B engine BUT, if you are using it in a 32 up car or truck, you can use a Model A head and Charlie Yapp makes adapters to use the B pump and block off the A outlet. Not like having a correct head but, it would work. I don't know about on a 33-34 vehicle but it would work on a 32 or any straight radiator car/truck.
Now, if you use it in an A, just plug the two steam holes like Columbia says, generally with 5/16 allen bolts, and install it like any A head. Other than these 2 holes, the B block is just like the A deck.