VCCA Home Forums Thread Like Summary - speed

Through a series of engine problems and events, I have wound up with a 261 engine from a 1958 truck. I drive my car daily except for winter when there is snow/salt on the road. I also make a few short trips. My Question is about highway speed. l have noticed that Gene and a few others mentioned that they drive at 70 mph on the interstate. My car is a power glide and am wondering if this is feasible in my car.

I have used a tach and GPS to check my RPM at different speeds. At 65 rpm the engine is turning about 3100 rpm. I might overthinking the whole thing, but what is your opinion on 70 mph on the highway. The engine has not been rebuilt but it is solid. No smoke but uses a little oil.(mostly leaks)

All help and advice appreciated, Pete

Maybe I am missing something. Did you change the rear axle ratio when you installed the 1954 engine and transmission? Based on the specifications for a 1951 car with a 4.11 rear axle ratio, 60 mph is about 3100 rpm. Most people install the 3.55 rear that was used with the PowerGlide cars. With that ratio the engine should run at about 2900 rpm at 65.

i wonder if you actually have a 3.70 rear axle. That works out to about 3000 rpm at 65 mph.

i would not be too concerned about running the 261 at the same engine speed. While the engine speed will definitely hurt gas mileage it is a full pressure lubricated engine.

Actually I am more concerned about steering, suspension, and brakes driving these classic cars at 70 mph.