Weird factory tach problems....

Ok dad and I finished up putting his dash bezel in and putting the Real Time Engineering(RTE) board in his factory tach on his 67 cuda 273. Got everything all connected and hooked up. Tried to start.....no go...checked for spark out the coil and nothing....weird as dad had it running earlier. What I did was unhook the tach wire that connects to the -ve on the coil and it fired right up. Then checked the tach, which prior to us installing the new board, didnt work properly. Well the tach is now "stuck" at about 4500 rpm and doesnt move, even with the battery cables unhooked. Dads car has the mopar elec ignition, Im not sure if that is causing the issue or not. Before we installed the tach in the bezel I checked for a short to ground on both connections on the back of the tach, and its all good(no continuity between each connector and case). I checked the factory wiring schematic and its done properly. One wire(dark blue) comes from fuse block to a push on style terminal on back of tach, the other wire comes from the -ve on the coil to the bulkhead connector and continues in passenger compartment to a spade terminal on back of tach(grey wire).

Any ideas as to why no start with wire hooked to -ve on coil? Also why is tach now "stuck" on 4500 rpm??