True enough. There was a plan to install the Merlin into a P-38 but it never happened. I believe the Rolls engines were superior to the Allisons. The turbo-charging set-up used in the P-38 was far too complex. The Shackleton patrol bomber was in active service until the early nineties powered by four Griffons. Anyway, I just enjoy speculating about what kinds of planes might have been.
The P-51’s were suckling up all the Packard-Merlins that were available. Curtiss-Wright stuffed a Merlin in a late model P-40 as an experiment, but went back to the Allison for the related production model. Even the post-war P-82 twin-Mustang used Allisons as Packard didn’t renew the licensing agreement.