My 1980 swb had a mildly built 454/th350/np205/35s/4.10s. I could cruise all day at 80-85 mph, 3,000-3,300 rpms. It was locked front and rear and in 4 low it would smoke all 4 tires down the street. I had rear disc so I couldn't brake and light em up. Either way I wanted lower gears and taller...