Trunk mounted battery/ rear seat firewall regulations/track legal....

I did a battery relocation kit in my 66, mainly because my fenderwell is....in need of attention, and it may go bye-bye, havent decided yet. anyway, maybe someone can pick up some ideas. made the switch bracket from a carter fuel pump bracket, hold down, cables, and rod assembly myself. I sealed the original vents in the caps, drilled two 1/4 inch holes, one in each cap, epoxy'd a 90 and a tee, connected them with vinyl hose, and routed a vent out on a soft plug in the trunk floor. braided cable to frame in the back, 2 gauge braided cable from front sub-frame to block, and 4 gauge braided cable from head to firewall. used 1/0 nickel plated copper core stereo cable for the positive side. works like a charm. cheers!