Oof, tough choice this one....
Has to be the Rolls-Royce Spey 202. Having seen two of these beast's power both one of my favourite aircraft and Thrust SSC (SuperSonic Car), then it has my vote
"Too long a sacrifice
Can make a stone of the heart.
O when may it suffice?
That is Heaven's part, our part
To murmur name upon name,
As a mother names her child
When sleep at last has come
On limbs that had run wild.
What is it but nightfall?
No, no, not night but death;
Was it needless death after all?" W.B Yates