Car designs have come a long way since then. My 1965 Mustang was also a blast from 0-100mph and a white knuckle floater at anything above that. I’d guess top speed of that Mustang was probably only about 120mph (had the 289 HiPo engine, around 270hp in a very light car). Won many a light to light race in that car. Many of the 350cuin cars I went up against could give it a good run for the money, some faster, many slower, but pretty much anything less than a 350 was no problem at all to beat in light to light racing (yes, the stupid things we did on Friday nights in the late 1970’s).
By comparison, my 1997 Porsche 911 gets to 100mph much much faster and then just hunkers down in a full squat as it climbs well over 120mph, zero float, perfectly planted. Top speed is over 170mph in the 911 IIRC, never had it near that, just about 130mph, and it behaved perfectly.