I find it hard to believe that the hissing, wheezing piece of sidevalve junk blessed with 36 bhp when new, capable of propelling my 100E Anglebox from 0-60 in 29.7 seconds of frenzied mechanical stress, was ever in the same league regarding tolerances as a Rolls Royce Merlin
See the bottom of Pg 58 of the 2010 Airlife impression. To quote from Pg 59 -
"
It took a or year so (to re-draw the 'prints)
, but it was enormous success, because, once the great Ford factory at Manchester started production, Merlins came out like shelling peas at a rate of 400 per week. And very good engines they were too, yet I have never seen mention of this massive contribution which the Ford Motor Company made to the building up of our airforces." - Sir Stanley Hooker.
Not Much Of An Engineer is well worth reading.