 Additional orders, already on the books, were canceled.With the cutback in production, the variants of the P-51H with different versions of the Merlin engine were produced in either limited numbers or terminated.These included the P-51L, similar to the P-51H but utilizing the V-1650-11 engine, which was never built; and its Dallas-built version, the P-51M, or NA-124, which utilized the V-1650-9A engine lacking water injection and therefore rated for lower maximum power, of which one was built out of the original 1629 ordered, serial number 45-11743.