There's a fairly complete history of R-3350 development and service in
wikipedia.
One additional factor working against the early R-3350s was the exhaust system design. The front row of cylinders had exhaust ports facing forward into a manifold upstream of the cylinders. This manifold preheated the cooling air for the cylinder heads - hardly a stroke of genius.
The P&W R-2800, by contrast, had all exhaust ports facing aft to avoid this preheating.