Yeah, I had a 1960 VW Bug, 6 Volt battery. I too installed an engine by myself using only a floor jack. Replaced the aging 36 HP engine with a newer rebuilt 40 HP engine. It had no gas gauge, just a lever above the gas pedal that you turned by foot to switch to the reserve tank, I think it was about an extra gallon of gas.
We had one just like it. A 1960. Top speed about 62 MPH. Maybe a little more going down a hill and less into a head wind.
Also remember you had to open the hood to fuel it up. It wasn’t until later they added the access to the fuel tank with a little trap door.