In 1953, the 'four pipe' 997 cc Ariel Square Four Mk II was released, with separate barrels, a re-designed cylinder head with four separate exhaust pipes from two cast-aluminium manifolds and a rocker-box combined with the inlet manifold.
In 1954, Ariel built prototypes of a Mk3 with Earles forks, but the model was never put into production [REF].