Confusion as to the engine.
In Wurger's article it stated 14S.M, but in the caption it said 145M.
The Merlin in question was an RM.14SM - which is the rating for some of the 100-series Merlins. The first Packard 100-series engine was the V-1650-9.
R = Rolls-Royce
M = Merlin
14 = rating
S = supercharged, aka fully supercharged (ie high altitude)
M = medium supercharged
The other 100-series ratings, that I know of, was the RM.16SM and RM.17SM.
Merlin 113 and 114 were rated RM.16SM. They were used in some late model Mosquitoes.
The Merlin 130/131 of teh de Havilland Hornet were RM.14SM.
RM.17SM was type tested but never went into service and no production engines were built, so no mark number was assigned.