Check your ground. and the grounds on the block. you should add some grounds to the block, and make sure the ground on the batt in the trunk is attached to the frame. also, did it kill batteries before? check your voltage when the car is running, should be 13.0 to 14.5 at the battery.
For the grounds to the block, you can use battery cable, regular wire, etc. just make sure you secure them under a bolt on the block (not the motor mounts) and there is no paint under them. same for the battery to frame, but only use a bbattery cable here.