I agree that the bulkhead plate is a great idea if not using a fuel cell. I think most racing rules require a plate to close off the interior to the trunk as well as the engine compartment. The firewall does that to the engine compartment, as long as any holes are sealed. The rear bulkhead I believe in most rules requires a minimum .040" aluminum to close of the trunk to the driver's compartment.
I see that many R-Model track car utilize the rear package shelf, but they really do not seal off the driver's compartment. I use the package tray on my car, nut I am using the fuel cell. I'm going to consider installing a bulkhead closure the next time the tank or rear package tray needs to be removed.
Don
gt350bp