I'll just say, if you want to keep costs down, I wouldn't go past 4:10's. Once I went into the 4:xx ratios, heat(@ cruise) became an issue, freeway speeds and fuel economy went into the crapper
A lot of truth there. I had 4.30s in my 65 Valiant. I had to find the sweet spot with "mileage" as it was my daily driver for almost four years. Ends up, ironically, 55MPH put me dead on the best mileage it could get. "Whatever that was". I never measured it. It was "around" 2800 RPM give or take if I remember. Really wasn't too bad.
