Jump07 wrote:
You mean 2x2 metal and washers on the underside of the car? ALL the way under? Like a plate, sandwiching the floor between the plate and the seat?
Yep.
As for mouting the seat to cage. Well it not really possible given the cage rules and geometry of the cars. You may however fab up a mount that welds to the sill and tunnel.
In pure forward impact the belts talk nearly all the load. However in a rear impact the rear seat mount will push in to the floor and front will pull up. It is the pulling up that can rip out the bolts from the floor pan. The belts don't do that much at all.