You must have short tires. I had 4.30s in my 65 Valiant and it only turned like 2850 at 55 or so. Wasn't bad at all. But then, I had 28 11-50s on the back.
Yeah, 255/60-15 approx. 27” Freeway cruise speeds here are 65-70 but at 55 I’m at 2500+/- which would be doable except you get run over, or left behind by the boys with od.