As long as the overall layout of this group of cars (Sprint, Midget, Silver Crown, Mini, Micro) is mandated by the various sanctioning bodies, and is accepted by the insurers, the exposed location of the fuel tank will remain an exposed location.

Given the required wheelbases, engine location, engine plate-to-rear axle distance, driver location, and a tail-tank stipulation, the inherent hazard will remain.
It can be mitigated by strengthening 1) the mounting of the tank shell, and 2) the rear bumper/tank guard.