I hate to bust your bubble, but the Merlin wins hands down, even over the Griffon.

Even if the Griffon was "better", it was the Merlin that, in its RR and Packard guises powered the major fighters and bombers.

The Allisons were good, solid engines, but no match for the overall performance of the Merlins.

Now, amongst the radials, I'd have to choose the Pratt & Whitney family over the Wrights - and both families were excellent and reliable performers.

Note that I'm limiting my subjective "comparisons" to the Allied designs.   The Daimler-Benz inline engines could arguably be considered "better engineered" and as such, as good, if not better than the Merlin.

Once they'd sorted the supercharger issues, the Merlin won hands down. No better all round engine during WWII (particularly after Ford started making them in the UK), and not many after either...

If you're after a good read, try Sir Stanley Hooker's autobiography "Not much of an Engineer". He was they chap who sorted the supercharger, and gave the Merlin its new lease of life...

The fact that the Mustang had to have the Merlin shows the Allison's engines flaws...

I never said for it to be the BEST.  I asked what is your FAVORITE!!  I don't believe that the p38 is the best (except in looks), its just my favorite.

Merlin. Best sounding engine ever.

Does the P-51 'Jumping Jacques' use the Merlin engine? Perhaps one of the best sounding aircraft I have ever seen. You should hear it, quite literally, scream when it pulls up into a barrel roll

Can't argue with the fact that the Merlin powered the best fighters of WW2 but I just love the growl of the Griffon. I grew up hearing a Griffon flying over my house and it just stuck. Also the Griffon engined Spits just look awesome As for best radial, Bristol Centaurus.