The Merlin 30, 32 and 34 were later engines based off the MK XII.
I did make a mistake on the climbing power, 2850rpm at 4lbs instead of 2850rpm at either 9 3/4s or 12 lbs
look at fold out chart in the rear of the book for differences.
I think they were based upon the Merlin XX and it's improved SC intake.