If you look at the photo you will see two different jacks and an axle support. Most people will opt for the professional garage jack to get their precious classic off the ground.
It is also the most obvious choice, at least if you have such a jack. But do not forget one thing: even when using this heavy-duty jack, it is absolutely irresponsible to lie under the car without the car relying securely on a set of metal feet or axle supports. This is because the hydraulic jack has a valve that ensures that the hydraulic oil goes from one chamber to the other, so that the jack is raised. That valve can suddenly break and the pressure disappears from the system like snow in the sun. The result is a jack that can no longer hold the weight, causing your car to hit the floor immediately. You can imagine that it is an extremely unpleasant feeling when the car starts to press your chest. A helper, if any, will also no longer raise the jack because it will not build up any more pressure. No matter how shaky the scissor jack, which is also in the photo, looks like: in fact it is safer than the garage jack. But also use stable supports there.
Photo and text Jacques van den Bergh