A.A. Rubbra:
“The “F” engine, later to be called the Kestrel, had been prompted by the success of the Curtiss D12 liquid-cooled engine in the USA. This engine used aluminium cylinder blocks with steel liners instead of separate steel cylinders with welded-on jackets, a construction wich considerably increaded the beam stiffness of the crankcase and the ability to use higher rpm and powers without crankcase trouble. Work on the “F” engine was further spurred on by the purchase, by the Fairey company, of a number of Curtiss D12 engines for installation in the Fairey Fox.”

Powerandpassion:
All the Rolls-Royce V12s from the Kestrel through to the Merlin used single piece blocks, with the exception of the Merlin I, and most marks of Merlin from the Mk22 onwards, from mid 1941. Ford were still building the highly successful Merlin XX as late as 1944, so clearly it shouldn`t have been, and wasn`t strangled at birth.
Naturally aspirated Kestrels, and others, also had carburettors in the vee of the engine.

Personally, I think the original comment by Paul Kennedy is poorly researched and plain wrong, but clearly Rolls-Royce were influenced by the aluminium single-piece block on the D12. but there are no detail similarities between the two engines.

Pete