You didn't say if this was a street or track car. But, back in the 70s when we didn't have many choices and less information, we always used snubbers. Mostly to save the rear U-joints.

They did that job, but you had to have the snubber fairly close to the body in order for it to do it's job. And man, did the car ride rough like that.

And yes, the floor needed re-enforced at the point of contact.