Need help with old Chevy versus Mopar debate

A fair comparison would be the 275 hp rated Mopar 340, A-body versus similar 275 hp 327 in Chevvies equivalent body/weight. I used to have a 66 Plymouth Valiant 273 4b. The previous owner, an acquaintance, raced it against Ford 289 4bbls, Fairlanes and Mustangs as well as Chevy 283s in similar sized bodies. He never lost...