'65 Mustang Hi-po vs '65 Formula S

SSVDP said
In general the Hi-Po 289 had the edge on the 273 Commando depending on drive rear axle etc.
But the Barracuda had superior handling.

I agree. But the hi-po 289 had a much hotter cam than the 273 Commando. Better comparison would be vs. the 289 four barrel. 225 hp rating vs. 235. Stock to stock, 273 was an easy winner. Just based on my own experience.