Back when I was using a 1959 3800 like a truck, not a pampered toy, I could cruise the slow lane of the interstate at around 60 MPH with no problems. That rig had a 4.56 rear end and 18" tube type tires. Yes, the engine made some noise, but it didn't hand grenade, and I drove it that way on a regular basis. The 58 Chevy Delray coupe that I drove in college in the mid-1960's, with a 235 3 speed setup, a 3.70 rear end, and 14" tires had no problem running 70 MPH or more virtually every time I drove home, 150 miles each way.
Jerry
