Check out this video of the McCulloch kart. Apparently, the company used to make karting engines, and also got into chassis development. Amazing what they had in 1961.
Shock absorbing rear suspension. Upholstered seat. The engine and rear axle was one assembly and could be removed to switch from one class to another (like Briggs to Rotax in today’s terms) during the same event…with only 4 bolts.
The video is from the old days when men were men and women dressed up like Barbie dolls and kissed the winning driver (rather than competing).