I installed a performance motor in my 76 Aspen RT and am having some stumble and stall issues. At high RPM it is barely noticeable but the car will stall at a stop sign or light, but start right up again with no trouble. When cold starting sometimes it starts right up and other times it seems to be only running on four cylenders and then stalls. It is obviously an ignition issue, i have a few wires left open from EGR, smog pump, and whatnot and was wondering if the ignition may be grounding out on the motor or chassis causing this. I have a 5 pin black box electronic ignition installed but have a 4 pin chrome box on the shelf. Any suggestions?