Best Aircraft Engine of WWII ?

This statement is simply nonsense. Spitfire IX was the stop gap version to counter FW-190.

Griffon Engined Spits suffered from poor range. They were "useless" in any practical field operations save intercepting incoming enemy raids against their home base.

Edit: ah drats, I see your link states the Griffon in XII was good intercepting against low level incoming enemy fighters. The range deficient and one stage blower didn't hamper the Spit so much that it wasn't usefull in that role. One stage blower combined with high displacement at that time of the war meant good low and medium altitude performance, but poor high altitude performance. The range was still extremely poor for any altitude for a griffon engined Spit.

 

Yes the Spit IX was a stop-gap. But that version had the Merlin!
Oli

 

Oops. See what you mean about the IX. Sorry, thought you meant it had Griffon.
Yes, the Spit did lose range in comparison with the "equivalent" Merlin variant, but then again Spit was designed as an interceptor, it's a typical British design as regards range. The Mk XII dropped to nearly the range of the Mk 1, but with 70% more power and 61 mph faster.
For information - just knocked this off:
And the best of the Merlin versions for range was the X, a stripped and lightened photo-recce bird.
Sorry, can''t agree with "useless".
Oli