Comparison 340 / 289

A friend of mine in hs had a 67 rustang with a built 390, and I mean built, 4 speed car, sounded like a 10 sec car, ran low 14's, very disappointing. I could keep up fender to fender with mach 1 mustangs with my 56 chev wagon 3800# and basically stock 283 4 speed.