Pictured here is a cast iron Simmons Super Power Head aftermarket high compression cylinder head for Model A's.
This head was produced in the early 1930s in a 5.5:1 compression ratio according to Simmons catalog information.
Note the "Licensed by Chrysler Motors" cast into the head. The head was not made by Chrysler, but the Ricardo combustion chamber design was used by Simmons under license from Chrysler.
See the link below for some history on Harry Ricardo's engine and combustion design research.
Note the placement of the spark plugs on this head. They are moved further away from the intake valve, which is a performance advantage.
Most Model A high compression heads retain the stock spark plug placement directly over the intake valve, where it is shrouded and not optimally placed.