what is the top speed of a 1961 jeep CJ5?

Jeep cj's were built for four their "All terain" four wheel drive ability, not top speed. You may get 90mph out of it if you are lucky. Being a 1961 and depending on how many miles are on the engine, you will probably blow the engine just trying. Have it put on a lift and make sure that the "U joints" are solid and the 4x4 works. Look at the places that 4x4's can take you. With this vehicle "chained up" there very few places that you can't go. If it runs and you are sure that everything works and is safe, you should try some mild four wheeling. These places usually are not close to any city. Check out what others are doing with their 4x4's. There are off road magazines and web sites that can show you the true potential of that vehicle. Gazateer atlas(topographic maps by state) and U.S forest service maps are a great source to find fun roads to take. This is a great vehicle, so have as much fun as I would!

I used to have a 1965 Jeep CJ5A Tuxedo Park with the optional Warn overdrive, and I topped out at 52 mph, 57 on a slight downhill slope, 45 on that same slope going uphill.

"driving" speed max 90 mph.